Neprilysin inhibitors

ABSTRACT

In one aspect, the invention relates to compounds having the formula: 
     
       
         
         
             
             
         
       
     
     where R 1 -R 6 , a, b, and X are as defined in the specification, or a pharmaceutically acceptable salt thereof. These compounds have neprilysin inhibition activity. In another aspect, the invention relates to pharmaceutical compositions comprising such compounds; methods of using such compounds; and processes and intermediates for preparing such compounds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/423,175, filed on Dec. 15, 2010; the entire disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel compounds havingneprilysin-inhibition activity. The invention also relates topharmaceutical compositions comprising such compounds, processes andintermediates for preparing such compounds and methods of using suchcompounds to treat diseases such as hypertension, heart failure,pulmonary hypertension, and renal disease.

2. State of the Art

Neprilysin (neutral endopeptidase, EC 3.4.24.11) (NEP), is anendothelial membrane bound Zn²⁺metallopeptidase found in many organs andtissues, including the brain, kidneys, lungs, gastrointestinal tract,heart, and the peripheral vasculature. NEP degrades and inactivates anumber of endogenous peptides, such as enkephalins, circulatingbradykinin, angiotensin peptides, and natriuretic peptides, the latterof which have several effects including, for example, vasodilation andnatriuresis/diuresis, as well as inhibition of cardiac hypertrophy andventricular fibrosis. Thus, NEP plays an important role in bloodpressure homeostasis and cardiovascular health.

NEP inhibitors, such as thiorphan, candoxatril, and candoxatrilat, havebeen studied as potential therapeutics. Compounds that inhibit both NEPand angiotensin-I converting enzyme (ACE) are also known, and includeomapatrilat, gempatrilat, and sampatrilat. Referred to as vasopeptidaseinhibitors, this latter class of compounds is described in Robl et al.(1999) Exp. Opin. Ther. Patents 9(12): 1665-1677.

SUMMARY OF THE INVENTION

The present invention provides novel compounds that have been found topossess neprilysin (NEP) enzyme inhibition activity. Accordingly,compounds of the invention are expected to be useful and advantageous astherapeutic agents for treating conditions such as hypertension andheart failure.

One aspect of the invention relates to a compound of formula I:

where:

R¹ is selected from —OR⁷ and —NR⁸R⁹;

R² is H or —P(O)(OH)₂ or R² is taken together with R⁷ to form —CR¹⁸R¹⁹—or is taken together with R⁸ to form —C(O)—;

X is a —C₁₋₉heteroaryl;

R³ is absent or is selected from H; halo; —C₀₋₅alkylene-OH; —NH₂;—C₁₋₆alkyl; —CF₃; —C₃₋₇cycloalkyl; —C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰;—C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³; —NHC(O)R²⁴; ═O; —NO₂; —C(CH₃)═N(OH);phenyl optionally substituted with one or two groups independentlyselected from halo, —OH, —CF₃, —OCH₃, —NHC(O)CH₃, and phenyl;naphthalenyl; pyridinyl; pyrazinyl; pyrazolyl optionally substitutedwith methyl; thiophenyl optionally substituted with methyl or halo;furanyl; and —CH₂-morpholinyl; and R³, when present, is attached to acarbon atom;

R⁴ is absent or is selected from H; —OH; —C₁₋₆alkyl;—C₁₋₂alkylene-COOR³⁵; —CH₂OC(O)CH(R³⁶)NH₂; —OCH₂OC(O)CH(R³⁶)NH₂;—OCH₂OC(O)CH₃; —CH₂OP(O)(OH)₂; —CH₂CH(OH)CH₂OH;—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl; pyridinyl; and phenyl or benzyloptionally substituted with one or more groups selected from halo,—COOR³⁵, —OCH₃, —OCF₃, and —SCF₃; and R⁴, when present, is attached to acarbon or nitrogen atom;

or R³ and R⁴ are taken together to form -phenylene-O—(CH₂)₁₋₃— or-phenylene-O—CH₂—CHOH—CH₂—;

a is 0 or 1; R⁵ is selected from halo, —CH₃, —CF₃, and —CN;

b is 0 or an integer from 1 to 3; each R⁶ is independently selected fromhalo, —OH, —CH₃, —OCH₃, and —CF₃;

R⁷ is selected from H, —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R¹⁰, —C₁₋₆alkylene-NR¹²R¹³, —C₁₋₆alkylene-C(O)R³¹,—C₀₋₆alkylenemorpholinyl; —C₁₋₆alkylene-SO₂—C₁₋₆alkyl;

R¹⁰ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR¹²R¹³, —CH[CH(CH₃)₂]—NH₂,—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, and —CH(NH₂)CH₂COOCH₃; and R¹² and R¹³are independently selected from H, —C₁₋₆alkyl, and benzyl; or R¹² andR¹³ are taken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or—(CH₂)₂—O—(CH₂)₂—; and R³¹ is selected from —O—C₁₋₆alkyl, —O-benzyl, and—NR¹²R¹³; R³² is —C₁₋₆alkyl or —C₀₋₆alkylene-C₆₋₁₀aryl;

R⁸ is selected from H, —OH, —OC(O)R¹⁴, —CH₂COOH, —O-benzyl, pyridyl, and—OC(S)NR¹⁵R¹⁶; R¹⁴ is selected from H, —C₁₋₆alkyl, —C₆₋₁₀aryl,—OCH₂—C₆₋₁₀aryl, —CH₂O—C₆₋₁₀aryl, and —NR¹⁵R¹⁶; and R¹⁵ and R¹⁶ areindependently selected from H and —C₁₋₄alkyl;

R⁹ is selected from H, —C₁₋₆alkyl, and —C(O)R¹⁷; and R¹⁷ is selectedfrom H, —C₁₋₆alkyl, —C₃₋₇cycloalkyl, —C₆₋₁₀aryl, and —C₁₋₆heteroaryl;

R¹⁸ and R¹⁹ are independently selected from H, —C₁₋₆alkyl, and—O—C₃₋₇cycloalkyl, or R¹⁸ and R¹⁹ are taken together to form ═O;

R²⁰ is selected from H and —C₁₋₆alkyl;

R²¹ and R³⁵ are independently selected from H, —C₁₋₆alkyl,—C₁₋₃alkylene-C₆₋₁₀aryl, —C₁₋₃alkylene-C₁₋₆heteroaryl, —C₃₋₇cycloalkyl,—[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R²⁵; —C₁₋₆alkylene-NR²⁷R²⁸,—C₁₋₆alkylene-C(O)R³³, —C₀₋₆alkylenemorpholinyl,—C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

R²⁵ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR²⁷R²⁸, —CH[CH(CH₃)₂]—NH₂,—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, and —CH(NH₂)CH₂COOCH₃; R²⁷ and R²⁸ areindependently selected from H, —C₁₋₆alkyl, and benzyl; or R²⁷ and R²⁸are taken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or —(CH₂)₂O(CH₂)₂—; R³³is selected from —O—C₁₋₆alkyl, —O-benzyl, and —NR²⁷R²⁸; and R³⁴ is—C₁₋₆alkyl or —C₀₋₆alkylene-C₆₋₁₀aryl;

R²² and R²³ are independently selected from H, —C₁₋₆alkyl, —CH₂COOH,—(CH₂)₂OH; —(CH₂)₂OCH₃, —(CH₂)₂SO₂NH₂, —(CH₂)₂N(CH₃)₂,—C₀₋₁alkylene-C₃₋₇cycloalkyl, and —(CH₂)₂-imidazolyl; or R²² and R²³ aretaken together to form a saturated or partially unsaturated—C₃₋₅heterocycle optionally substituted with halo, —OH, —COOH, or—CONH₂; and optionally containing an oxygen atom in the ring;

R²⁴ is selected from —C₁₋₆alkyl; —C₀₋₁alkylene-O—C₁₋₆alkyl; phenyloptionally substituted with halo or —OCH₃; and —C₁₋₉heteroaryl; and

R³⁶ is selected from H, —CH(CH₃)₂, phenyl, and benzyl;

where each alkyl group in R¹, R³, and R⁴ is optionally substituted with1 to 8 fluoro atoms; and;

where the methylene linker on the biphenyl is optionally substitutedwith one or two —C₁₋₆alkyl groups or cyclopropyl;

or a pharmaceutically acceptable salt thereof.

Another aspect of the invention relates to pharmaceutical compositionscomprising a pharmaceutically acceptable carrier and a compound of theinvention. Such compositions may optionally contain other therapeuticagents. Accordingly, in yet another aspect of the invention, apharmaceutical composition comprises a compound of the invention as thefirst therapeutic agent, one or more secondary therapeutic agent, and apharmaceutically acceptable carrier. Another aspect of the inventionrelates to a combination of active agents, comprising a compound of theinvention and a second therapeutic agent. The compound of the inventioncan be formulated together or separately from the additional agent(s).When formulated separately, a pharmaceutically acceptable carrier may beincluded with the additional agent(s). Thus, yet another aspect of theinvention relates to a combination of pharmaceutical compositions, thecombination comprising: a first pharmaceutical composition comprising acompound of the invention and a first pharmaceutically acceptablecarrier; and a second pharmaceutical composition comprising a secondtherapeutic agent and a second pharmaceutically acceptable carrier. Inanother aspect, the invention relates to a kit containing suchpharmaceutical compositions, for example where the first and secondpharmaceutical compositions are separate pharmaceutical compositions.

Compounds of the invention possess NEP enzyme inhibition activity, andare therefore expected to be useful as therapeutic agents for treatingpatients suffering from a disease or disorder that is treated byinhibiting the NEP enzyme or by increasing the levels of its peptidesubstrates. Thus, one aspect of the invention relates to a method oftreating patients suffering from a disease or disorder that is treatedby inhibiting the NEP enzyme, comprising administering to a patient atherapeutically effective amount of a compound of the invention. Anotheraspect of the invention relates to a method of treating hypertension,heart failure, or renal disease, comprising administering to a patient atherapeutically effective amount of a compound of the invention. Stillanother aspect of the invention relates to a method for inhibiting a NEPenzyme in a mammal comprising administering to the mammal, a NEPenzyme-inhibiting amount of a compound of the invention.

Since compounds of the invention possess NEP inhibition activity, theyare also useful as research tools. Accordingly, one aspect of theinvention relates to a method of using a compound of the invention as aresearch tool, the method comprising conducting a biological assay usinga compound of the invention. Compounds of the invention can also be usedto evaluate new chemical compounds. Thus another aspect of the inventionrelates to a method of evaluating a test compound in a biological assay,comprising: (a) conducting a biological assay with a test compound toprovide a first assay value; (b) conducting the biological assay with acompound of the invention to provide a second assay value; wherein step(a) is conducted either before, after or concurrently with step (b); and(c) comparing the first assay value from step (a) with the second assayvalue from step (b). Exemplary biological assays include a NEP enzymeinhibition assay. Still another aspect of the invention relates to amethod of studying a biological system or sample comprising a NEPenzyme, the method comprising: (a) contacting the biological system orsample with a compound of the invention; and (b) determining the effectscaused by the compound on the biological system or sample.

Yet another aspect of the invention relates to processes andintermediates useful for preparing compounds of the invention.Accordingly, another aspect of the invention relates to a process ofpreparing compounds of formula I, comprising the step of coupling acompound of formula 1 with a compound of formula 2:

to produce a compound of formula I; where P¹ is H or an amino-protectinggroup selected from t-butoxycarbonyl, trityl, benzyloxycarbonyl,9-fluorenylmethoxycarbonyl, formyl, trimethylsilyl, andt-butyldimethylsilyl; and where the process further comprisesdeprotecting the compound of formula 1 when P¹ is an amino protectinggroup; and where R¹-R⁶, a, b, and X are as defined for formula I.Another aspect of the invention relates to a process of preparing apharmaceutically acceptable salt of a compound of formula I, comprisingcontacting a compound of formula I in free acid or base form with apharmaceutically acceptable base or acid. In other aspects, theinvention relates to products prepared by any of the processes describedherein, as well as novel intermediates used in such process. In oneaspect of the invention novel intermediates have formulas 1, 6, 7, 8, 9,or a salt thereof, as defined herein.

Yet another aspect of the invention relates to the use of a compound offormula I or a pharmaceutically acceptable salt thereof, for themanufacture of a medicament, especially for the manufacture of amedicament useful for treating hypertension, heart failure, or renaldisease. Another aspect of the invention relates to use of a compound ofthe invention for inhibiting a NEP enzyme in a mammal. Still anotheraspect of the invention relates to the use of a compound of theinvention as a research tool. Other aspects and embodiments of theinvention are disclosed herein.

DETAILED DESCRIPTION OF THE INVENTION Definitions

When describing the compounds, compositions, methods and processes ofthe invention, the following terms have the following meanings unlessotherwise indicated. Additionally, as used herein, the singular forms“a,” “an,” and “the” include the corresponding plural forms unless thecontext of use clearly dictates otherwise. The terms “comprising”,“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements. Allnumbers expressing quantities of ingredients, properties such asmolecular weight, reaction conditions, and so forth used herein are tobe understood as being modified in all instances by the term “about,”unless otherwise indicated. Accordingly, the numbers set forth hereinare approximations that may vary depending upon the desired propertiessought to be obtained by the present invention. At least, and not as anattempt to limit the application of the doctrine of equivalents to thescope of the claims, each number should at least be construed in lightof the reported significant digits and by applying ordinary roundingtechniques.

The term “alkyl” means a monovalent saturated hydrocarbon group whichmay be linear or branched. Unless otherwise defined, such alkyl groupstypically contain from 1 to 10 carbon atoms and include, for example,—C₁₋₄alkyl, —C₁₋₅alkyl, —C₂₋₅alkyl, —C₁₋₆alkyl, —C₁₋₈alkyl, and—C₁₋₁₀alkyl. Representative alkyl groups include, by way of example,methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl,n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl and the like.

When a specific number of carbon atoms is intended for a particular termused herein, the number of carbon atoms is shown preceding the term assubscript. For example, the term “—C₁₋₆alkyl” means an alkyl grouphaving from 1 to 6 carbon atoms, and the term “—C₃₋₇cycloalkyl” means acycloalkyl group having from 3 to 7 carbon atoms, respectively, wherethe carbon atoms are in any acceptable configuration.

The term “alkylene” means a divalent saturated hydrocarbon group thatmay be linear or branched. Unless otherwise defined, such alkylenegroups typically contain from 0 to 10 carbon atoms and include, forexample, —C₀₋₁alkylene-, —C₀₋₆alkylene-, —C₁₋₃allylene-, and—C₁₋₆alkylene-. Representative alkylene groups include, by way ofexample, methylene, ethane-1,2-diyl (“ethylene”), propane-1,2-diyl,propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl and the like. It isunderstood that when the alkylene term include zero carbons such as—C₀₋₁alkylene-, such terms are intended to include the absence of carbonatoms, that is, the alkylene group is not present except for a covalentbond attaching the groups separated by the alkylene term.

The term “aryl” means a monovalent aromatic hydrocarbon having a singlering (i.e., phenyl) or one or more fused rings. Fused ring systemsinclude those that are fully unsaturated (e.g., naphthalene) as well asthose that are partially unsaturated (e.g.,1,2,3,4-tetrahydronaphthalene). Unless otherwise defined, such arylgroups typically contain from 6 to 10 carbon ring atoms and include, forexample, —C₆₋₁₀aryl. Representative aryl groups include, by way ofexample, phenyl and naphthalene-1-yl, naphthalene-2-yl, and the like.

The term “cycloalkyl” means a monovalent saturated carbocyclichydrocarbon group. Unless otherwise defined, such cycloalkyl groupstypically contain from 3 to 10 carbon atoms and include, for example,—C₃₋₅cycloalkyl, —C₃₋₆cycloalkyl and —C₃₋₇cycloalkyl. Representativecycloalkyl groups include, by way of example, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl and the like.

The term “halo” means fluoro, chloro, bromo and iodo.

The term “heterocycle” is intended to include monovalent unsaturated(aromatic) heterocycles having a single ring or two fused rings as wellas monovalent saturated and partially unsaturated groups having a singlering or multiple condensed rings. The heterocycle ring can contain from3 to 15 total ring atoms, of which 1 to 14 are ring carbon atoms, and 1to 4 are ring heteroatoms selected from nitrogen, oxygen or sulfur.Typically, however, the heterocycle ring contains from 3 to 10 totalring atoms, of which 1 to 9 are ring carbon atoms, and 1 to 4 are ringheteroatoms. The point of attachment is at any available carbon ornitrogen ring atom. Exemplary heterocycles include, for example,—C₁₋₂heterocycle, —C₃₋₅heterocycle, —C₂₋₆heterocycle, —C₃₋₁₂heterocycle,—C₅₋₉heterocycle, —C₁₋₉heterocycle, —C₁₋₁₁heterocycle, and—C₁₋₁₄heterocyle.

Monovalent unsaturated heterocycles are also commonly referred to as“heteroaryl” groups. Unless otherwise defined, heteroaryl groupstypically contain from 5 to 10 total ring atoms, of which 1 to 9 arering carbon atoms, and 1 to 4 are ring heteroatoms, and include, forexample, —C₁₋₉heteroaryl and —C₅₋₉heteroaryl. Representative heteroarylgroups include, by way of example, pyrrole (e.g., 3-pyrrolyl and2H-pyrrol-3-yl), imidazole (e.g., 2-imidazolyl), furan (e.g., 2-furyland 3-furyl), thiophene (e.g., 2-thienyl), triazole (e.g.,1,2,3-triazolyl and 1,2,4-triazolyl), pyrazole (e.g., 1H-pyrazol-3-yl),oxazole (e.g., 2-oxazolyl), isoxazole (e.g., 3-isoxazolyl), thiazole(e.g., 2-thiazolyl and 4-thiazolyl), and isothiazole (e.g.,3-isothiazolyl), pyridine (e.g., 2-pyridyl, 3-pyridyl, and 4-pyridyl),pyridylimidazole, pyridyltriazole, pyrazine, pyridazine (e.g.,3-pyridazinyl), pyrimidine (e.g., 2-pyrimidinyl), tetrazole, triazine(e.g., 1,3,5-triazinyl), indolyle (e.g., 1H-indol-2-yl, 1H-indol-4-yland 1H-indol-5-yl), benzofuran (e.g., benzofuran-5-yl), benzothiophene(e.g., benzo[b]thien-2-yl and benzo[b]thien-5-yl), benzimidazole,benzoxazole, benzothiazole, benzotriazole, quinoline (e.g., 2-quinolyl),isoquinoline, quinazoline, quinoxaline and the like.

Monovalent saturated heterocycles typically contain from 3 to 10 totalring atoms, of which 2 to 9 are ring carbon atoms, and 1 to 4 are ringheteroatoms, and include, for example —C₃₋₅heterocycle. Representativemonovalent saturated heterocycles include, by way of example, monovalentspecies of pyrrolidine, imidazolidine, pyrazolidine, piperidine,1,4-dioxane, morpholine, thiomorpholine, piperazine, 3-pyrroline and thelike. In some instances, moieties may be described as being takentogether to form a saturated —C₃₋₅heterocycle optionally containing anoxygen atom in the ring. Such groups include:

Monovalent partially unsaturated heterocycles typically contain from 3to 10 total ring atoms, of which 2 to 11 are ring carbon atoms, and 1 to3 are ring heteroatoms, and include, for example —C₃₋₅heterocycle and—C₂₋₁₂heterocycle. Representative monovalent partially unsaturatedheterocycles include, by way of example, pyran, benzopyran, benzodioxole(e.g., benzo[1,3]dioxol-5-yl), tetrahydropyridazine,2,5-dihydro-1H-pyrrole, dihydroimidazole, dihydrotriazole,dihydrooxazole, dihydroisoxazole, dihydrothiazole, dihydroisothiazole,dihydrooxadiazole, dihydrothiadiazole, tetrahydropyridazine,hexahydropyrroloquinoxaline, and dihydrooxadiazabenzo[e]azulene. In someinstances, moieties may be described as being taken together to form apartially unsaturated —C₃₋₅heterocycle. Such groups include:

The term “optionally substituted” means that group in question may beunsubstituted or it may be substituted one or several times, such as 1to 3 times, or 1 to 5 times, or 1 to 8 times. For example, a phenylgroup that is “optionally substituted” with halo atoms, may beunsubstituted, or it may contain 1, 2, 3, 4, or 5 halo atoms; and analkyl group that is “optionally substituted” with fluoro atoms may beunsubstituted, or it may contain 1, 2, 3, 4, 5, 6, 7, or 8 fluoro atoms.Similarly, a group that is “optionally substituted” with one or two—C₁₋₆alkyl groups, may be unsubstituted, or it may contain one or two—C₁₋₆alkyl groups.

As used herein, the phrase “having the formula” or “having thestructure” is not intended to be limiting and is used in the same waythat the term “comprising” is commonly used. For example, if onestructure is depicted, it is understood that all stereoisomer andtautomer forms are encompassed, unless stated otherwise.

The term “pharmaceutically acceptable” refers to a material that is notbiologically or otherwise unacceptable when used in the invention. Forexample, the term “pharmaceutically acceptable carrier” refers to amaterial that can be incorporated into a composition and administered toa patient without causing unacceptable biological effects or interactingin an unacceptable manner with other components of the composition. Suchpharmaceutically acceptable materials typically have met the requiredstandards of toxicological and manufacturing testing, and include thosematerials identified as suitable inactive ingredients by the U.S. Foodand Drug administration.

The term “pharmaceutically acceptable salt” means a salt prepared from abase or an acid which is acceptable for administration to a patient,such as a mammal (for example, salts having acceptable mammalian safetyfor a given dosage regime). However, it is understood that the saltscovered by the invention are not required to be pharmaceuticallyacceptable salts, such as salts of intermediate compounds that are notintended for administration to a patient. Pharmaceutically acceptablesalts can be derived from pharmaceutically acceptable inorganic ororganic bases and from pharmaceutically acceptable inorganic or organicacids. In addition, when a compound of formula I contains both a basicmoiety, such as an amine, pyridine or imidazole, and an acidic moietysuch as a carboxylic acid or tetrazole, zwitterions may be formed andare included within the term “salt” as used herein. Salts derived frompharmaceutically acceptable inorganic bases include ammonium, calcium,copper, ferric, ferrous, lithium, magnesium, manganic, manganous,potassium, sodium, and zinc salts, and the like. Salts derived frompharmaceutically acceptable organic bases include salts of primary,secondary and tertiary amines, including substituted amines, cyclicamines, naturally-occurring amines and the like, such as arginine,betaine, caffeine, choline, N,N′-dibenzylethylenediamine, diethylamine,2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine,ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine,glucosamine, histidine, hydrabamine, isopropylamine, lysine,methylglucamine, morpholine, piperazine, piperadine, polyamine resins,procaine, purines, theobromine, triethylamine, trimethylamine,tripropylamine, tromethamine and the like. Salts derived frompharmaceutically acceptable inorganic acids include salts of boric,carbonic, hydrohalic (hydrobromic, hydrochloric, hydrofluoric orhydroiodic), nitric, phosphoric, sulfamic and sulfuric acids. Saltsderived from pharmaceutically acceptable organic acids include salts ofaliphatic hydroxyl acids (for example, citric, gluconic, glycolic,lactic, lactobionic, malic, and tartaric acids), aliphaticmonocarboxylic acids (for example, acetic, butyric, formic, propionicand trifluoroacetic acids), amino acids (for example, aspartic andglutamic acids), aromatic carboxylic acids (for example, benzoic,p-chlorobenzoic, diphenylacetic, gentisic, hippuric, and triphenylaceticacids), aromatic hydroxyl acids (for example, o-hydroxybenzoic,p-hydroxybenzoic, 1-hydroxynaphthalene-2-carboxylic and3-hydroxynaphthalene-2-carboxylic acids), ascorbic, dicarboxylic acids(for example, fumaric, maleic, oxalic and succinic acids), glucoronic,mandelic, mucic, nicotinic, orotic, pamoic, pantothenic, sulfonic acids(for example, benzenesulfonic, camphosulfonic, edisylic, ethanesulfonic,isethionic, methanesulfonic, naphthalenesulfonic,naphthalene-1,5-disulfonic, naphthalene-2,6-disulfonic andp-toluenesulfonic acids), xinafoic acid, and the like.

As used herein, the term “prodrug” is intended to mean an inactive (orsignificantly less active) precursor of a drug that is converted intoits active form in the body under physiological conditions, for example,by normal metabolic processes. Such compounds may not possesspharmacological activity at NEP, but may be administered orally orparenterally and thereafter metabolized in the body to form compoundsthat are pharmacologically active at NEP. Exemplary prodrugs includeesters such as C₁₋₆alkylesters and aryl-C₁₋₆alkylesters. In oneembodiment, the active compound has a free carboxyl and the prodrug isan ester derivative thereof, i.e., the prodrug is an ester such as—C(O)OCH₂CH₃. Such ester prodrugs are then converted by solvolysis orunder physiological conditions to be the free carboxyl compound. Theterm is also intended to include certain protected derivatives ofcompounds of formula I that may be made prior to a final deprotectionstage. Thus, all protected derivatives and prodrugs of compounds formulaI are included within the scope of the invention.

The term “therapeutically effective amount” means an amount sufficientto effect treatment when administered to a patient in need thereof, thatis, the amount of drug needed to obtain the desired therapeutic effect.For example, a therapeutically effective amount for treatinghypertension is an amount of compound needed to, for example, reduce,suppress, eliminate, or prevent the symptoms of hypertension, or totreat the underlying cause of hypertension. In one embodiment, atherapeutically effective amount is that amount of drug needed to reduceblood pressure or the amount of drug needed to maintain normal bloodpressure. On the other hand, the term “effective amount” means an amountsufficient to obtain a desired result, which may not necessarily be atherapeutic result. For example, when studying a system comprising a NEPenzyme, an “effective amount” may be the amount needed to inhibit theenzyme.

The term “treating” or “treatment” as used herein means the treating ortreatment of a disease or medical condition (such as hypertension) in apatient, such as a mammal (particularly a human) that includes one ormore of the following: (a) preventing the disease or medical conditionfrom occurring, i.e., preventing the reoccurrence of the disease ormedical condition or prophylactic treatment of a patient that ispre-disposed to the disease or medical condition; (b) ameliorating thedisease or medical condition, i.e., eliminating or causing regression ofthe disease or medical condition in a patient; (c) suppressing thedisease or medical condition, i.e., slowing or arresting the developmentof the disease or medical condition in a patient; or (d) alleviating thesymptoms of the disease or medical condition in a patient. For example,the term “treating hypertension” would include preventing hypertensionfrom occurring, ameliorating hypertension, suppressing hypertension, andalleviating the symptoms of hypertension (for example, lowering bloodpressure). The term “patient” is intended to include those mammals, suchas humans, that are in need of treatment or disease prevention or thatare presently being treated for disease prevention or treatment of aspecific disease or medical condition, as well as test subjects in whichcompounds of the invention are being evaluated or being used in anassay, for example an animal model.

All other terms used herein are intended to have their ordinary meaningas understood by those of ordinary skill in the art to which theypertain.

In one aspect, the invention relates to compounds of formula I:

or a pharmaceutically acceptable salt thereof.

As used herein, the term “compound of the invention” includes allcompounds encompassed by formula I such as the species embodied informulas Ia and Ib, as well as the compounds encompassed by formulas IIand III, and species thereof. In addition, the compounds of theinvention may also contain several basic or acidic groups (for example,amino or carboxyl groups) and therefore, such compounds can exist as afree base, free acid, or in various salt forms. All such salt forms areincluded within the scope of the invention. Furthermore, the compoundsof the invention may also exist as prodrugs. Accordingly, those skilledin the art will recognize that reference to a compound herein, forexample, reference to a “compound of the invention” or a “compound offormula I” includes a compound of formula I as well as pharmaceuticallyacceptable salts and prodrugs of that compound unless otherwiseindicated. Further, the term “or a pharmaceutically acceptable saltand/or prodrug thereof” is intended to include all permutations of saltsand prodrugs, such as a pharmaceutically acceptable salt of a prodrug.Furthermore, solvates of compounds of formula I are included within thescope of this invention.

The compounds of formula I may contain one or more chiral centers andtherefore, these compounds may be prepared and used in variousstereoisomeric forms. Accordingly, the invention also relates to racemicmixtures, pure stereoisomers (e.g., enantiomers and diastereoisomers),stereoisomer-enriched mixtures, and the like unless otherwise indicated.When a chemical structure is depicted herein without anystereochemistry, it is understood that all possible stereoisomers areencompassed by such structure. Thus, for example, the terms “compound offormula I,” “compounds of formula II,” and so forth, are intended toinclude all possible stereoisomers of the compound. Similarly, when aparticular stereoisomer is shown or named herein, it will be understoodby those skilled in the art that minor amounts of other stereoisomersmay be present in the compositions of the invention unless otherwiseindicated, provided that the utility of the composition as a whole isnot eliminated by the presence of such other isomers. Individualstereoisomers may be obtained by numerous methods that are well known inthe art, including chiral chromatography using a suitable chiralstationary phase or support, or by chemically converting them intodiastereoisomers, separating the diastereoisomers by conventional meanssuch as chromatography or recrystallization, then regenerating theoriginal stereoisomer.

Additionally, where applicable, all cis-trans or E/Z isomers (geometricisomers), tautomeric forms and topoisomeric forms of the compounds ofthe invention are included within the scope of the invention unlessotherwise specified. For example, if X is depicted as (R⁴ beinghydrogen):

it is understood that the compound may also exist in a tautomeric formsuch as:

More specifically, compounds of formula I can contain at least onechiral center indicated by the symbol * in the following formula:

In one embodiment of the invention, the carbon atom identified by thesymbol * has the (R) configuration. This embodiment of the invention isshown in formula Ia:

In this embodiment, compounds have the (R) configuration at the * carbonatom or are enriched in a stereoisomeric form having the (R)configuration at this carbon atom.

In another embodiment, the carbon atom identified by the symbol * hasthe (S) configuration. This embodiment of the invention is shown informula Ib:

In this embodiment, compounds have the (S) configuration at the * carbonatom or are enriched in a stereoisomeric form having the (S)configuration at this carbon atom.

In some embodiments, in order to optimize the therapeutic activity ofthe compounds of the invention, e.g., to treat hypertension, it may bedesirable that the carbon atom identified by the * symbol has aparticular (R) or (S) configuration or is enriched in a stereoisomericform having such configuration. For example, in one embodiment, thecompounds of the invention have the (R) configuration of formula Ia areenriched in a stereoisomeric form having the (R) configuration, and inanother embodiment, the compounds of the invention have the (S)configuration of formula Ib, or are enriched in a stereoisomeric formhaving the (S) configuration. In other embodiments, the compounds of theinvention are present as a racemic mixture, for example as a mixture ofenantiomers of formula Ia and Ib.

The compounds of the invention, as well as those compounds used in theirsynthesis, may also include isotopically-labeled compounds, that is,where one or more atoms have been enriched with atoms having an atomicmass different from the atomic mass predominately found in nature.Examples of isotopes that may be incorporated into the compounds offormula I, for example, include, but are not limited to, ²H, ³H, ¹³C,¹⁴C_(,) ¹⁵N, ¹⁸O, ¹⁷O, ³⁵S, ³⁶Cl, and ¹⁸F. Of particular interest arecompounds of formula I enriched in tritium or carbon-14 which can beused, for example, in tissue distribution studies; compounds of formulaI enriched in deuterium especially at a site of metabolism resulting,for example, in compounds having greater metabolic stability; andcompounds of formula I enriched in a positron emitting isotope, such as¹¹C, ¹⁸F, ¹⁵O and ¹³N, which can be used, for example, in PositronEmission Topography (PET) studies.

The nomenclature used herein to name the compounds of the invention isillustrated in the Examples herein. This nomenclature has been derivedusing the commercially available AutoNom software (MDL, San Leandro,Calif.).

Representative Embodiments

The following substituents and values are intended to providerepresentative examples of various aspects and embodiments of theinvention. These representative values are intended to further defineand illustrate such aspects and embodiments and are not intended toexclude other embodiments or to limit the scope of the invention. Inthis regard, the representation that a particular value or substituentis preferred is not intended in any way to exclude other values orsubstituents from the invention unless specifically indicated.

In one aspect, this invention relates to compounds of formula I:

R¹ is selected from —OR⁷ and —NR⁸R⁹. The R⁷ moiety is selected from:

H;

—C₁₋₈alkyl, e.g., —CH₃, —CH₂CH₃, —(CH₂)₂CH₃, —CH(CH₃)₂, —CH₂CH(CH₃)₂,—(CH₂)₃CH₃, —(CH₂)₄CH₃, —(CH₂)₂CH(CH₃)₂, —(CH₂)₅CH₃, and —(CH₂)₆CH₃;

—C₁₋₃alkylene-C₆₋₁₀aryl, e.g., benzyl;

—C₁₋₃alkylene-C₁₋₉heteroaryl, e.g., —CH₂-pyridinyl and—(CH₂)₂-pyridinyl;

—C₃₋₇cycloalkyl, e.g., cyclopentyl;

—[(CH₂)₂O]₁₋₃CH₃, e.g., —(CH₂)₂OCH₃ and —[(CH₂)₂O]₂CH₃;

—C₁₋₆allylene-OC(O)R¹⁰, e.g., —CH₂OC(O)CH₃, —CH₂OC(O)CH₂CH₃,—CH₂OC(O)(CH₂)₂CH₃, —CH₂CH(CH₃)OC(O)CH₂CH₃, —CH₂OC(O)OCH₃,—CH₂OC(O)OCH₂CH₃, —CH(CH₃)OC(O)OCH₂CH₃, —CH(CH₃)OC(O)O—CH(CH₃)₂,—CH₂CH(CH₃)OC(O)-cyclopentyl, —CH₂OC(O)O-cyclopropyl,—CH(CH₃)—OC(O)—O-cyclohexyl, —CH₂OC(O)O-cyclopentyl,—CH₂CH(CH₃)OC(O)-phenyl, —CH₂OC(O)O-phenyl, —CH₂OC(O)—CH[CH(CH₃)₂]—NH₂,—CH₂OC(O)—CH[CH(CH₃)₂]—NHC(O)OCH₃, and —CH(CH₃)OC(O)—CH(NH₂)CH₂COOCH₃;

—C₁₋₆alkylene-NR¹²R¹³, e.g., —(CH₂)₂—N(CH₃)₂,

—C₁₋₆alkylene-C(O)R³¹, e.g., —CH₂C(O)OCH₃, —CH₂C(O)O-benzyl,—CH₂C(O)—N(CH₃)₂, and

—C₀₋₆alkylenemorpholinyl, e.g., —(CH₂)₂-morpholinyl and—(CH₂)₃-morpholinyl:

—C₁₋₆alkylene-SO₂—C₁₋₆alkyl, e.g., —(CH₂)₂SO₂CH₃;

for example,

The R¹⁰ moiety is selected from:

—C₁₋₆alkyl, e.g., CH₃ and —CH₂CH₃;

—O—C₁₋₆alkyl, e.g., —OCH₃, O—CH₂CH₃, and O—CH(CH₃)₂;

—C₃₋₇cycloalkyl, e.g., cyclopentyl);

—O—C₃₋₇cycloalkyl, e.g., —O-cyclopropyl, —O-cyclohexyl, and—O-cyclopentyl;

phenyl;

—O-phenyl;

—NR¹²R¹³;

—CH[CH(CH₃)₂]—NH₂;

—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, e.g., —CH[CH(CH₃)₂]—NHC(O)OCH₃; and

—CH(NH₂)CH₂COOCH₃.

The R¹² and R¹³ moieties are independently selected from H, —C₁₋₆alkyl(e.g., CH₃), and benzyl. Alternately, the R¹² and R¹³ moieties can betaken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or —(CH₂)₂O(CH₂)₂—, forexample to form a group such as:

The R³¹ moiety is selected from —O—C₁₋₆alkyl, e.g., —OCH₃, —O-benzyl,and —NR¹²R¹³, e.g., —N(CH₃)₂, and

The R³² moiety is —C₁₋₆alkyl (e.g., —CH₃ and —C(CH₃)₃) or—C₀₋₆alkylene-C₆₋₁₀aryl.

The R⁸ moiety is selected from:

H;

—OH;

—OC(O)R¹⁴, e.g., —OC(O)CH₃, —OC(O)-phenyl, —OC(O)—OCH₂-phenyl,—OC(O)—CH₂O-phenyl, —OC(O)(NH₂), and —OC(O)[N(CH₃)₂;

—CH₂COOH;

—O-benzyl;

pyridyl; and

—OC(S)NR¹⁵R¹⁶, e.g., —OC(S)NH₂ and —OC(S)N(CH₃)₂.

The R¹⁴ moiety is selected from:

H;

—C₁₋₆alkyl, e.g., —CH₃;

—C₆₋₁₀aryl, e.g., phenyl;

—OCH₂—C₆₋₁₀aryl, e.g., —OCH₂-phenyl;

—CH₂O—C₆₋₁₀aryl, e.g., —CH₂O-phenyl; and

—NR¹⁵R¹⁶, e.g., —NH₂ and N(CH₃)₂.

The R¹⁵ and R¹⁶ moieties are independently selected from H and—C₁₋₄alkyl.

The R⁹ is moiety selected from H, —C₁₋₆alkyl (e.g., —CH₃), and —C(O)R¹⁷(e.g., —C(O)H). The R¹⁷ moiety is selected from H, —C₁₋₆alkyl (e.g.,—CH₂CH₃), —C₃₋₇cycloalkyl (e.g., cyclopropyl), —C₆₋₁₀aryl (e.g.,phenyl), and —C₁₋₉heteroaryl (e.g., pyridine).

In addition, each alkyl group in R¹ is optionally substituted with 1 to8 fluoro atoms. For example, when R¹ is —OR⁷ and R⁷ is —C₁₋₈alkyl, R¹can also be a group such as —OCH(CH₃)CF₃, —OCH₂CF₂CF₃, —OCH(CF₃)₂,—O(CH₂)₂CF₃, —OCH(CH₂F)₂, —OC(CF₃)₂CH₃, and —OCH(CH₃)CF₂CF₃.

In one embodiment, R¹ is —OR⁷, and R⁷ is selected from H, —C₁₋₈alkyl,—C₁₋₃alkylene-C₆₋₁₀aryl, —C₀₋₆alkylenemorpholinyl, and

where R³² is —C₁₋₆alkyl; and where each alkyl group is optionallysubstituted with 1 to 8 fluoro atoms. In other embodiments thesecompounds have formula III.

In one embodiment, R¹ is selected from —OR⁷ and —NR⁸R⁹, where R⁷ is H,R⁸ is H or —OH, and R⁹ is H. In other embodiments these compounds haveformula III.

In another embodiment, R¹ is —OR⁷, where R⁷ is selected from —C₁₋₈alkyl,—C₁₋₃alkylene-C₆₋₁₀aryl, —C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl,—[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R¹⁰, —C₁₋₆alkylene-NR¹²R¹³,—C₁₋₆alkylene-C(O)R³¹, —C₀₋₆alkylenemorpholinyl;—C₁₋₆alkylene-SO₂—C₁₋₆alkyl;

In yet another embodiment, R¹ is —NR⁸R⁹; where R⁸ is selected from—OC(O)R¹⁴, —CH₂COOH, —O-benzyl, pyridyl, and —OC(S)NR¹⁵R¹⁶; and R⁹ is H.In yet another embodiment, R¹ is —NR⁸R⁹, where R⁸ is H or —OH; and R⁹ is—C₁₋₆alkyl or —C(O)R¹⁷. In yet another embodiment, R¹ is —NR⁸R⁹, whereR⁸ is selected from —OC(O)R¹⁴, —CH₂COOH, —O-benzyl, pyridyl, and—OC(S)NR¹⁵R¹⁶; and R⁹ is —C₁₋₆alkyl or —C(O)R¹⁷. In another embodimentthese compounds have formula III. In one aspect of the invention, thesecompounds may find particular utility as prodrugs or as intermediates inthe synthetic procedures described herein. For example, in oneembodiment, R¹ is —OR⁷ and R⁷ is —C₁₋₆alkylene-OC(O)R¹⁰, such asO—CH(CH₃)OC(O)—O-cyclohexyl:

making the compound a cilexetil ester; or R¹ is —OR⁷ and R⁷ is—C₀₋₆alkylenemorpholinyl such as —O—(CH₂)₂-morpholinyl:

making the compound a 2-morpholinoethyl or mofetil ester; or R¹ is —OR⁷and R⁷ is

such as —O—CH₂-5-methyl-[1,3]dioxol-2-one:

making the compound a medoxomil ester.

R² is H or —P(O)(OH)₂. R² can also be taken together with R⁷ to form—CR¹⁸R¹⁹— or taken together with R⁸ to form —C(O)—. R¹⁸ and R¹⁹ areindependently selected from H, —C₁₋₆alkyl, and —O—C₃₋₂cycloalkyl, or R¹⁸and R¹⁹ may be taken together to form ═O. In one embodiment, R² is H. Inanother embodiment this compound has formula III.

When R² is taken together with R² to form —CR¹⁸R¹⁹—, this embodiment canbe depicted as:

and when R¹⁸ and R¹⁹ are taken together to form ═O, this embodiment canbe depicted as:

When R² is taken together with R⁸ to form —C(O)—, this embodiment can bedepicted as:

In one aspect of the invention, these compounds may find particularutility as prodrugs or as intermediates in the synthetic proceduresdescribed herein. In another embodiment these compounds have formulaIII. Compounds where R² is —P(O)(OH)₂ may also find utility as prodrugs.

The “X” moiety is a —C₁₋₉heteroaryl, and the point of attachment is atany available carbon or nitrogen ring atom. Note that in someembodiments, R³ and/or R⁴ may be absent. When present, R³ is on anyavailable carbon atom. When present, R⁴ is on any available carbon atomor nitrogen atom. Exemplary —C₁₋₉heteroaryl rings include, by way ofillustration and not limitation:

pyrazole rings such as:

specific examples of which include:

imidazole rings such as:

specific examples of which include:

triazole rings, including 1,2,3-triazole such as:

as well as 1,2,4-triazole such as:

benzotriazole rings such as:

specific examples of which include:

furan rings:

specific examples of which include:

pyrrole rings:

specific examples of which include:

tetrazole rings such as:

pyrazine rings:

a specific example of which includes:

thiophene rings:

specific examples of which include:

oxazole rings:

specific examples of which include:

isoxazole rings:

specific examples of which include:

thiazole rings:

specific examples of which include:

isothiazole rings:

oxadiazole rings, including [1,2,4]oxadiazole such as:

as well as [1,2,3]oxadiazole such as:

and [1,3,4]oxadiazole:

thiadiazole rings, including [1,2,4]thiadiazole such as:

as well as [1,2,3]thiadiazole such as:

and [1,3,4]thiadiazole:

pyridazine rings:

pyridine rings:

specific examples of which include:

pyrimidine rings:

specific examples of which include:

pyran rings such as

benzimidazole rings such as:

specific examples of which include:

benzoxazole rings such as:

specific examples of which include:

benzothiazole rings such as:

specific examples of which include:

pyridylimidazole rings such as:

a specific example of which includes:

and

pyridyltriazole rings such as:

specific examples of which include:

In one particular embodiment, X is selected from pyrazole, imidazole,triazole, benzotriazole, furan, pyrrole, tetrazole, pyrazine, thiophene,oxazole, isoxazole, thiazole, isothiazole, oxadiazole, thiadiazole,pyridazine, pyridine, pyrimidine, pyran, benzimidazole, benzoxazole,benzothiazole, pyridylimidazole, and pyridyltriazole.

It is understood that some —C₁₋₉heteroaryl rings can exist in atautomeric form, and that such tautomeric forms are part of theinvention and are encompassed by the term “heteroaryl.” Therefore, if acompound is depicted with a —C₁₋₉heteroaryl ring, it is understood thatthe compound can also exist in a tautomeric form and vice versa, andthat both forms are covered by the invention.

—C₁₋₉heteroaryl ring exemplary ring exemplary tautomer(s) pyrazole

imidazole

triazole

oxazole

thiazole

isothiazole

oxadiazole

thiadiazole

pyridazine

In one particular embodiment, X is selected from pyrazole, triazole,benzotriazole, tetrazole, oxazole, isoxazole, thiazole, pyridazine,pyrimidine, and pyridyltriazole. In still another embodiment X is anisoxazole, and in one specific embodiment, have formula III:

where R¹-R⁶, a, and b are as defined for formula I. In yet anotherembodiment, the compounds of the invention have formula IIIa:

where R¹, R⁵, R⁶, a, and b, are as defined for formula I. In stillanother embodiment, the compounds of the invention have formula IIIb:

where R¹, R⁵, R⁶, a, and b, are as defined for formula I.

The R³ moiety can be absent. When present, R³ is attached to a carbonatom in the “X” group, and is selected from:

H;

halo, e.g., chloro and fluoro;

—C₀₋₅alkylene-OH, e.g., —OH, —CH₂OH, —CH(OH)CH₃, and —C(CH₃)₂—OH;

—NH₂;

—C₁₋₆alkyl, e.g., —CH₃, —(CH₂)₂CH₃, —CH(CH₃)₂, and —(CH₂)₃—CH₃;

—CF₃;

—C₃₋₇cycloalkyl, e.g., cyclopropyl and cyclohexyl;

—C₀₋₂alkylene-O—C₁₋₆alkyl, e.g., —OCH₃, —OCH₂CH₃, —CH₂—OCH₃, and—(CH₂)₂—OCH₃;

—C(O)R²⁰, e.g., —C(O)H and —C(O)CH₃;

—C₀₋₁alkylene-COOR²¹, e.g., —COOH, —CH₂—COOH, —C(O)O—CH₂CH₃,—C(O)O—(CH₂)₂OCH₃—C(O)O—CH₂OC(O)CH₃, —CH₂—C(O)O—CH₂OC(O)CH₃,—C(O)O—CH₂OC(O)O—CH₃, —CH₂—C(O)O—CH₂OC(O)O—CH₃,—C(O)O—CH(CH₃)OC(O)O—CH₂CH₃, —C(O)O—CH(CH₃)OC(O)O—CH(CH₃)₂,—C(O)O—CH₂CH(CH₃)OC(O)-cyclopentyl, —C(O)O—CH₂OC(O)O-cyclopropyl,—C(O)O—CH(CH₃)—OC(O)—O-cyclohexyl, —C(O)O—CH₂OC(O)O-cyclopentyl,—C(O)O—CH₂CH(CH₃)OC(O)-phenyl, —C(O)O—CH₂OC(O)O-phenyl,—C(O)O—CH₂-pyridine, —C(O)O—CH₂-pyrrolidine, —C(O)O—(CH₂)₂-morpholinyl,—C(O)O—(CH₂)₃-morpholinyl, and —C(O)O—(CH₂)₂—SO₂—CH₃;

—C(O)NR²²R²³, e.g., —C(O)NH₂, —C(O)NHCH₃, —C(O)N(CH₃)₂,—C(O)NH—(CH₂)₂CH₃, —C(O)NH—CH₂COOH, —C(O)NH—(CH₂)₂—OH,—C(O)NH—(CH₂)₂—N(CH₃)₂, —C(O)NH-cyclopropyl, —C(O)NH—(CH₂)₂-imidazolyl,—C(O)N(CH₃)—CH₂CH(CH₃)₂, and —C(O)N(CH₃)[(CH₂)₂OCH₃];

—NHC(O)R²⁴, e.g., —NHC(O)—CH₂CH₃, —NHC(O)—(CH₂)₃CH₃, —NHC(O)O—CH₂CH₃,—NHC(O)—CH₂—OCH₃, —NHC(O)-2-methoxyphenyl, —NHC(O)-2-chlorophenyl, and—NHC(O)-2-pyridine;

═O;

—NO₂;

—C(CH₃)═N(OH);

phenyl optionally substituted with one or two groups independentlyselected from halo, —OH, —CF₃, —OCH₃, —NHC(O)CH₃, and phenyl (e.g.,phenyl, 2-chlorophenyl, 2-fluorophenyl, 2-hydroxyphenyl,2-trifluoromethylphenyl, 2-methoxyphenyl, 3-chlorophenyl,3-fluorophenyl, 3-methoxyphenyl, 3—NHC(O)CH₃-phenyl, 4-chlorophenyl,4-fluorophenyl, 4-methoxyphenyl, 4-biphenyl, 2,5-dichlorophenyl,2,5-dimethoxyphenyl, 2,4-dichlorophenyl, 2-methoxy, 5-fluorophenyl, and3,4-dichlorophenyl);

naphthalenyl;

pyridinyl;

pyrazinyl;

pyrazolyl optionally substituted with methyl;

thiophenyl optionally substituted with methyl or halo (e.g., chloro);

furanyl; and

—CH₂-morpholinyl.

The R²⁰ moiety is selected from H and —C₁₋₆allyl (e.g., —CH₃). The R²¹moiety is selected from:

H;

—C₁₋₆alkyl, e.g., —CH₃ and —CH₂CH₃;

—C₁₋₃alkylene-C₆₋₁₀aryl;

—C₁₋₃alkylene-C₁₋₉heteroaryl, e.g., —CH₂-pyridine;

—C₃₋₇cycloalkyl;

—[(CH₂)₂O]₁₋₃CH₃, e.g., —(CH₂)₂OCH₃;

—C₁₋₆alkylene-OC(O)R²⁵, e.g., —CH₂OC(O)CH₃, —CH₂OC(O)O—CH₃,—CH₂OC(O)O—CH₃, —CH(CH₃)OC(O)O—CH₂CH₃, —CH(CH₃)OC(O)O—CH(CH₃)₂,—CH₂CH(CH₃)OC(O)-cyclopentyl, —CH₂OC(O)O-cyclopropyl,—CH(CH₃)—OC(O)—O-cyclohexyl, —CH₂OC(O)O-cyclopentyl,—CH₂CH(CH₃)OC(O)-phenyl, and —CH₂OC(O)O-phenyl;

—C₁₋₆alkylene-NR²⁷R²⁸, e.g., —CH₂-pyrrolidine;

—C₁₋₆alkylene-C(O)R³³;

—C₀₋₆alkylenemorpholinyl, e.g., —(CH₂)₂-morpholinyl and—(CH₂)₃-morpholinyl:

—C₁₋₆alkylene-SO₂—C₁₋₆alkyl, e.g., —(CH₂)₂—SO₂—CH₃;

The R²² and R²³ moieties are independently selected from:

H;

—C₁₋₆alkyl, e.g., —CH₃ and —(CH₂)₂CH₃;

—CH₂COOH;

—(CH₂)₂OH;

—(CH₂)₂OCH₃;

—(CH₂)₂SO₂NH₂;

—(CH₂)₂N(CH₃)₂;

—C₀₋₁alkylene-C₃₋₇cycloalkyl, e.g., cyclopropyl and —CH₂-cyclopropyl;and

—(CH₂)₂-imidazolyl.

R²² and R²³ may also be taken together to form a saturated or partiallyunsaturated —C₃₋₅heterocycle optionally substituted with halo, —OH,—COOH, or —CONH₂, and optionally containing an oxygen atom in the ring.Saturated —C₃₋₅heterocycles include azetidine, pyrrolidine, piperidineand morpholine, such that exemplary R³ groups include:

Partially unsaturated —C₃₋₅heterocycles include 2,5-dihydro-1H-pyrrole,such that exemplary R³ groups include:

The R²⁴ moiety is selected from:

—C₁₋₆alkyl, e.g., —CH₂CH₃ and —(CH₂)₃CH₃;

—C₀₋₁alkylene-O—C₁₋₆alkyl, e.g., —O—CH₂CH₃ and —CH₂—OCH₃;

phenyl optionally substituted with halo or —OCH₃, e.g., -2-chlorophenylor -2-methoxyphenyl; and

—C₁₋₉heteroaryl, e.g., 2-pyridine.

R²⁵ is selected from:

—C₁₋₆alkyl, e.g., —CH₃, —CH₂CH₃, and —(CH₂)₃CH₃;

—O—C₁₋₆alkyl, e.g., —OCH₃, —OCH₂CH₃, and —OCH(CH₃)₂;

—C₃₋₇cycloalkyl, e.g., cyclopentyl;

—O—C₃₋₇cycloalkyl, e.g., —O-cyclopropyl, —O-cyclopentyl, and—O-cyclohexyl;

phenyl;

—O-phenyl;

—NR²⁷R²⁸;

—CH[CH(CH₃)₂]—NH₂;

—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, e.g., —CH[CH(CH₃)₂]—NHC(O)OCH₃; and

—CH(NH₂)CH₂COOCH₃.

R²⁷ and R²⁸ are independently selected from H, —C₁₋₆alkyl, and benzyl,or R²⁷ and R²⁸ are taken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or—(CH₂)₂O(CH₂)₂—; R³³ is selected from —O—C₁₋₆alkyl, —O-benzyl, and—NR²⁷R²⁸; and R³⁴ is —C₁₋₆alkyl (e.g., —CH₃ and —C(CH₃)₃) or—C₀₋₆alkylene-C₆₋₁₀aryl.

In addition, each alkyl group in R³ is optionally substituted with 1 to8 fluoro atoms. For example, when R³ is —C₀₋₁alkylene-COOR²¹ and R²¹ is—C₁₋₆alkyl, R³ can also be a group such as —COOCH(CH₃)CF₃,—COOCH₂CF₂CF₃, —COOCH(CF₃)₂, —COO(CH₂)₂CF₃, —COOCH(CH₂F)₂,—COOC(CF₃)₂CH₃, and —COOCH(CH₃)CF₂CF₃.

In one embodiment, R³ is absent or is selected from H; halo;—C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; phenyl optionally substituted with one or two groupsindependently selected from halo, —OH, and —OCH₃; pyridinyl; andpyrazinyl; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is H or —C₁₋₆alkyl; R²³ isselected from —C₁₋₆alkyl, —(CH₂)₂OH, —(CH₂)₂OCH₃, —(CH₂)₂SO₂NH₂, and—C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together to forma saturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo or —OH, and optionally containing an oxygen atomin the ring; and R²⁴ is phenyl substituted with —OCH₃. In otherembodiments these compounds have formula III.

In one embodiment, R³ is absent or is selected from H; halo;—C₀₋₅alkylene-OH; —NH₂; —C₁₋₆alkyl; —CF₃; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; —NO₂; —C(CH₃)═N(OH); phenyl optionally substituted withone or two groups independently selected from halo, —OH, —CF₃, —OCH₃,—NHC(O)CH₃, and phenyl; naphthalenyl; pyridinyl; pyrazinyl; pyrazolyloptionally substituted with methyl; thiophenyl optionally substitutedwith methyl or halo; furanyl; and —CH₂-morpholinyl; and R²¹ is H. Inother embodiments these compounds have formula III.

In another embodiment, R³ is —C₀₋₁alkylene-COOR²¹, and R²¹ is selectedfrom —C₁₋₆alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl, —C₁₋₃alkylene-C₁₋₉heteroaryl,—C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R²⁵;—C₁₋₆alkylene-NR²⁷R²⁸, —C₁₋₆alkylene-C(O)R³³, —C₀₋₆alkylenemorpholinyl,—C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

In one aspect of the invention, these compounds may find particularutility as prodrugs or as intermediates in the synthetic proceduresdescribed herein. In other embodiments these compounds have formula III.

The R⁴ moiety can be absent. When present, R⁴ is attached to a carbon ornitrogen atom in the “X” group, and is selected from:

H;

—OH;

—C₁₋₆alkyl, e.g., —CH₃;

—C₁₋₂alkylene-COOR³⁵, e.g., —CH₂COOH and —(CH₂)₂—COOH;

—CH₂OC(O)CH(R³⁶)NH₂, e.g., —CH₂OC(O)CH[CH(CH₃)₂]NH₂;

—OCH₂OC(O)CH(R³⁶)NH₂, e.g., —OCH₂OC(O)CH[CH(CH₃)₂]NH₂;

—OCH₂OC(O)CH₃;

—CH₂OP(O)(OH)₂;

—CH₂CH(OH)CH₂OH;

—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl;

pyridinyl; and

phenyl or benzyl optionally substituted with one or more groups selectedfrom halo, —COOR³⁵, —OCH₃, —OCF₃, and —SCF₃ (e.g., 4-chlorophenyl,3-methoxyphenyl, 2,4-dichlorophenyl, 3,4-dichlorophenyl, 2-chloro,5-fluorophenyl, 3-trifluoromethoxy, 4-chlorophenyl,3-trifluoromethylsulfanyl, 4-chlorophenyl, 2,6-difluoro, 4-chlorophenyl,2-chlorobenzyl, 3-chlorobenzyl, 4-chlorobenzyl, 3-carboxybenzyl,4-carboxybenzyl, 3-methoxybenzyl, 2-chloro, 5-fluorobenzyl, 3-chloro,5-fluorobenzyl, 2-fluoro, 4-chlorobenzyl, 3-chloro, 4-fluorobenzyl,3-OCF3,4-chlorobenzyl, 3-SCF3,4-chlorobenzyl, 2,6-difluoro,3-chlorobenzyl, 2,6-difluoro, 4-chlorobenzyl, and 2,3,5,6-tetrafluoro,4-methoxy benzyl).

The R³⁵ moiety is selected from:

H;

—C₁₋₆alkyl, e.g., —CH₃ and —CH₂CH₃;

—C₁₋₃alkylene-C₆₋₁₀aryl;

—C₁₋₃alkylene-C₁₋₉heteroaryl, e.g., —CH₂-pyridine;

—C₃₋₇cycloalkyl;

—[(CH₂)₂O]₁₋₃CH₃, e.g., —(CH₂)₂OCH₃;

—C₁₋₆alkylene-OC(O)R²⁵, e.g., —CH₂OC(O)CH₃, —CH₂OC(O)O—CH₃,—CH₂OC(O)O—CH₃, —CH(CH₃)OC(O)O—CH₂CH₃, —CH(CH₃)OC(O)O—CH(CH₃)₂,—CH₂CH(CH₃)OC(O)-cyclopentyl, —CH₂OC(O)O-cyclopropyl,—CH(CH₃)—OC(O)—O-cyclohexyl, —CH₂OC(O)O-cyclopentyl,—CH₂CH(CH₃)OC(O)-phenyl, and —CH₂OC(O)O-phenyl;

—C₁₋₆alkylene-NR²⁷R²⁸, e.g., —CH₂-pyrrolidine;

—C₁₋₆alkylene-C(O)R³³;

—C₀₋₆alkylenemorpholinyl, e.g., —(CH₂)₂-morpholinyl and—(CH₂)₃-morpholinyl:

—C₁₋₆alkylene-SO₂—C₁₋₆alkyl, e.g., —(CH₂)₂—SO₂—CH₃;

The R²⁵, R²⁷, R²⁸, R³³, and R³⁴ moieties are defined above. The R³⁶moiety is selected from H, —CH(CH₃)₂, phenyl, and benzyl.

In addition, each alkyl group in R⁴ is optionally substituted with 1 to8 fluoro atoms. For example, when R⁴ is —C₁₋₂alkylene-COOR³⁵ and R³⁵ is—C₁₋₆alkyl, R⁴ can also be a group such as —COOCH(CH₃)CF₃,—COOCH₂CF₂CF₃, —COOCH(CF₃)₂, —COO(CH₂)₂CF₃, —COOCH(CH₂F)₂,—COOC(CF₃)₂CH₃, and —COOCH(CH₃)CF₂CF₃.

The R⁴ moiety can also be taken together with R³ to form-phenylene-O—(CH₂)₁₋₃— or -phenylene-O—CH₂—CHOH—CH₂—. For purposes ofillustration only, these embodiments are depicted below with X beingpyrazole. It is understood that other X groups can be used also.

In another particular embodiment, R⁴ is selected from H; —OH;—C₁₋₂alkylene-COOR³⁵; pyridinyl; and phenyl or benzyl optionallysubstituted with one or more groups selected from halo and —OCH₃; andR³⁵ is H. In other embodiments these compounds have formula III.

In one embodiment, R⁴ is absent or is selected from H; —OH; —C₁₋₆allyl;—C₁₋₂alkylene-COOR³⁵; —CH₂OC(O)CH(R³⁶)NH₂, —CH₂CH(OH)CH₂OH; pyridinyl;and phenyl or benzyl optionally substituted with one or more groupsselected from halo, —COOR³⁵, —OCH₃, —OCF₃, and —SCF₃; and R³⁵ is H. Inother embodiments these compounds have formula III.

In another embodiment, R⁴ is selected from —OCH₂OC(O)CH₃;—CH₂OP(O)(OH)₂; —C₁₋₂alkylene-COOR³⁵; and phenyl or benzyl substitutedwith at least one —COOR³⁵ group; where R³⁵ is selected from —C₁₋₆alkyl,—C₁₋₃ alkylene-C₆₋₁₀aryl, —C₁₋₃ alkylene-C₁₋₉heteroaryl,—C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R²⁵;—C₁₋₆alkylene-NR²⁷R²⁸, —C₁₋₆alkylene-C(O)R³³, —C₀₋₆alkylenemorpholinyl,—C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

In one aspect of the invention, these compounds may find particularutility as prodrugs or as intermediates in the synthetic proceduresdescribed herein. In other embodiments these compounds have formula III.

The numbering for the R⁵ and R⁶ groups is as follows:

The integer “a” is 0 or 1. The R⁵ moiety, when present, is selected fromhalo, —CH₃, —CF₃, and —CN. In one embodiment, a is 0. In anotherembodiment, a is 1, and R⁵ is selected from halo and —CN, such as2-chloro, 2-fluoro, 3-cyano, 3-chloro, or 3-fluoro. The integer “b” is 0or an integer from 1 to 3. The R⁶ moiety, when present, is independentlyselected from halo, —OH, —CH₃, —OCH₃, and —CF₃. In one embodiment, b is0. In another embodiment, b is 1 and R⁶ is selected from Cl, F, —OH,—CH₃, —OCH₃, and —CF₃, such 2′-chloro, 3′-chloro, 2′-fluoro, 3′-fluoro,2′-hydroxy, 3′-hydroxy, 3′-methyl, 2′-methoxy, or 3′-trifluoromethyl. Inone embodiment, b is 2 and R⁶ is 2′-fluoro-5′-chloro, 2′,5′-dichloro,2′,5′-difluoro, 2′-methyl-5′-chloro, 3′-fluoro-5′-chloro,3′-hydroxy-5′-chloro, 3′,5′-dichloro, 3′,5′-difluoro,2′-methoxy-5′-chloro, 2′-methoxy-5′-fluoro, 2′-hydroxy-5′-fluoro,2′-fluoro-3′-chloro, 2′-hydroxy-5′-chloro, or 2′-hydroxy-3′-chloro; andin another embodiment, b is 2 and each R⁶ is independently halo, —OH,—CH₃, or —OCH₃, for example, 2′-fluoro-5′-chloro, 2′,5′-dichloro,2′-methyl-5′-chloro, 3′-hydroxy-5′-chloro, 3′,5′-dichloro,3′,5′-difluoro, 2′-methoxy-5′-chloro, 2′-methoxy-5′-fluoro,3′-fluoro-5′-chloro, 2′-hydroxy-5′-fluoro, 2′-fluoro-3′-chloro,2′-hydroxy-5′-chloro, or 2′-hydroxy-3′-chloro. In another embodiment, bis 3 and each R⁶ is independently halo or —CH₃, such as2′-methyl-3′,5′-dichloro or 2′-fluoro-3′-methyl-5′-chloro. In yetanother embodiment, a is 1 and b is 1 and R⁵ and R⁶ are independentlyhalo, for example, 3-chloro and 3′ chloro. In other embodiments thesecompounds have formula III. Of particular interest are compounds of theformulas:

The methylene linker on the biphenyl is optionally substituted with oneor two —C₁₋₆alkyl groups or cyclopropyl. For example, in one embodiment,the methylene linker on the biphenyl is unsubstituted; in anotherembodiment, the methylene linker on the biphenyl is substituted with one—C₁₋₆alkyl group (e.g., —CH₃); and in yet another embodiment, themethylene linker on the biphenyl is substituted with two —C₁₋₆alkylgroups (e.g., two —CH₃ groups); in another embodiment, the methylenelinker on the biphenyl is substituted with a cyclopropyl group. Theseembodiments are depicted, respectively, as:

In another embodiment, R¹ is OR⁷; R² is H; X is selected from pyrazole,triazole, benzotriazole, tetrazole, oxazole, isoxazole, thiazole,pyridazine, pyrimidine, and pyridyltriazole; R³ is absent or is selectedfrom H; halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; phenyl optionally substituted with one or two groupsindependently selected from halo, —OH, and —OCH₃; pyridinyl; andpyrazinyl; R⁴ is selected from H; —OH; —C₁₋₂alkylene-COOR³⁵; pyridinyl;and phenyl or benzyl optionally substituted with one or more groupsselected from halo and —OCH₃; a is 0; or a is 1 and R⁵ is selected fromhalo and —CN; b is 0; or b is 1 and R⁶ is selected from Cl, F, —OH,—CH₃, —OCH₃, and —CF₃; or b is 2 and each R⁶ is independently halo, —OH,CH₃, or —OCH₃; or b is 3 and each R⁶ is independently halo or CH₃; R⁷ isselected from H, —C₁₋₈alkyl, —C₁₋₃ alkylene-C₆₋₁₀aryl,—C₀₋₆alkylenemorpholinyl, and

R³² is —C₁₋₆alkyl; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is H or —C₁₋₆alkyl;R²³ is selected from —C₁₋₆alkyl, —(CH₂)₂OH, —(CH₂)₂OCH₃, —(CH₂)₂SO₂NH₂,and —C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together toform a saturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo or —OH, and optionally containing an oxygen atomin the ring; R²⁴ is phenyl substituted with —OCH₃; and R³⁵ is H; andwhere each alkyl group in R¹ is optionally substituted with 1 to 8fluoro atoms.

In still another embodiment, R¹ is OR⁷; R² is H; X is selected frompyrazole, triazole, benzotriazole, tetrazole, oxazole, isoxazole,thiazole, pyridazine, and pyrimidine; R³ is absent or is selected fromH; halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; phenyl substituted with one or two groups independentlyselected from halo, —OH, and —OCH₃; pyridinyl; and pyrazinyl; R⁴ isselected from H, —OH, and phenyl optionally substituted with a halogroup; a is 0; or a is 1 and R⁵ is halo; b is 0; or b is 1 and R⁶ ishalo or —CH₃; or b is 2 and each R⁶ is independently halo, —OH, CH₃, or—OCH₃; R²⁶ is —C₁₋₆alkyl; R²¹ is H; R²² is —C₁₋₆alkyl; R²³ is —C₁₋₆alkylor —C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together toform a saturated —C₃₋₅heterocycle optionally substituted with halo or—OH; R²⁴ is phenyl substituted with —OCH₃; and R⁷ is as defined forformula I.

A particular group of compounds of formula I are those disclosed in U.S.Provisional Application No. 61/423,175, filed on Dec. 15, 2010. Thisgroup includes compounds of formula II:

where: R¹ is selected from —OR⁷ and NR⁸R⁹; R⁷ is selected from H;—C₁₋₆alkyl; —C₁₋₃alkylene-C₆₋₁₀aryl; —C₁₋₃alkylene-C₁₋₉heteroaryl;—C₃₋₇cycloalkyl; —(CH₂)₂OCH₃; —C₁₋₆alkylene-OC(O)R¹⁰; —CH₂-pyridine;—CH₂-pyrrolidine; —C₀₋₆alkylenemorpholine; —C₁₋₆alkylene-SO₂—C₁₋₆alkyl;

where R¹⁰ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR¹²R¹³, and —CH(NH₂)CH₂COOCH₃;and R¹² and R¹³ are independently selected from H, —C₁₋₆alkyl, andbenzyl, or R¹² and R¹³ are taken together as —(CH₂)₃₋₆—; R⁸ is selectedfrom H; —OH; —OC(O)R¹⁴; —CH₂COOH; —O-benzyl; pyridyl; and —OC(S)NR¹⁵R¹⁶;where R¹⁴ is selected from H, —C₁₋₆alkyl, —C₆₋₁₀aryl, —OCH₂—C₆₋₄₀aryl,—CH₂O—C₆₋₁₀aryl, and NR¹⁵R¹⁶; and R¹⁵ and R¹⁶ are independently selectedfrom H and —C₁₋₄alkyl; R⁹ is selected from H; —C₁₋₆alkyl; and —C(O)R¹⁷;where R¹⁷ is selected from H; —C₁₋₆alkyl; —C₃₋₇cycloalkyl; —C₆₋₁₀aryl;and —C₁₋₉heteroaryl; R² is H or is taken together with R¹ to form—OCHR¹⁸R¹⁹— or —NHC(O)—; where R¹⁸ and R¹⁹ are independently selectedfrom H, —C₁₋₆alkyl, and —O—C₃₋₇cycloalkyl, or R¹⁸ and R¹⁹ are takentogether to form ═O; X is a —C₁₋₉heteroaryl or a partially unsaturated—C₃₋₅heterocycle; R³ is absent or is selected from H; halo;—C₀₋₅alkylene-OH; —NH₂; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₁alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-C(O)OR²¹;—C(O)NR²²R²³; —NHC(O)R²⁴; phenyl optionally substituted with one groupselected from halo, —CF₃, —OCH₃, —NHC(O)CH₃, and phenyl; napthyl;pyridine; pyrazine; pyrazole optionally substituted with methyl;thiophene optionally substituted with methyl; and furan; and R³, whenpresent, is attached to a carbon atom; R²⁰ is selected from H and—C₁₋₆alkyl; R²¹ is selected from H; —C₁₋₆alkyl; —C₁₋₃alkylene-C₆₋₄₀aryl;—C₁₋₃alkylene-C₁₋₉heteroaryl; —C₃₋₇cycloalkyl; —(CH₂)₂OCH₃;—C₁₋₆alkylene-OC(O)R²⁵; —CH₂-pyridine; —CH₂-pyrrolidine;—C₀₋₆alkylenemorpholine; —C₁₋₆alkylene-SO₂—C₁₋₆alkyl;

where R²⁵ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR²⁷R²⁸, and —CH(NH₂)CH₂COOCH₃;and R²⁷ and R²⁸ are independently selected from H, —C₁₋₆alkyl, andbenzyl, or R²⁷ and R²⁸ are taken together as —(CH₂)₃₋₆—; R²² and R²³ areindependently selected from H; —C₁₋₆alkyl; —CH₂COOH; —(CH₂)₂OH;—(CH₂)₂OCH₃; —(CH₂)₂SO₂NH₂; —(CH₂)₂N(CH₃)₂; —C₃₋₇cycloalkyl; and—(CH₂)₂-imidazole; or R²² and R²³ are taken together to form a saturatedor partially unsaturated —C₃₋₅heterocycle optionally substituted with—OH, —COOH, or —CONH₂; and optionally containing an oxygen atom in thering; R²⁴ is selected from —C₁₋₆alkyl; —O—C₁₋₆alkyl; —CH₂—O—C₁₋₆alkyl;phenyl substituted with —OCH₃; and pyridine; R⁴ is selected from H;—C₁₋₆alkyl; phenyl or benzyl substituted with one or more groupsselected from halo, —COOH, —OCH₃, —OCF₃, and —SCF₃; and R⁴ is attachedto a carbon or nitrogen atom; a is 0 or 1; R⁵ is halo or CF₃; and b is 0or 1; R⁶ is halo; or a pharmaceutically acceptable salt thereof.

In addition, particular compounds of formula I that are of interestinclude those set forth in the Examples below, as well apharmaceutically acceptable salt thereof.

General Synthetic Procedures

Compounds of the invention can be prepared from readily availablestarting materials using the following general methods, the proceduresset forth in the Examples, or by using other methods, reagents, andstarting materials that are known to those of ordinary skill in the art.Although the following procedures may illustrate a particular embodimentof the invention, it is understood that other embodiments of theinvention can be similarly prepared using the same or similar methods orby using other methods, reagents and starting materials known to thoseof ordinary skill in the art. It will also be appreciated that wheretypical or preferred process conditions (for example, reactiontemperatures, times, mole ratios of reactants, solvents, pressures,etc.) are given, other process conditions can also be used unlessotherwise stated. In some instances, reactions were conducted at roomtemperature and no actual temperature measurement was taken. It isunderstood that room temperature can be taken to mean a temperaturewithin the range commonly associated with the ambient temperature in alaboratory environment, and will typically be in the range of about 18°C. to about 30° C. In other instances, reactions were conducted at roomtemperature and the temperature was actually measured and recorded.While optimum reaction conditions will typically vary depending onvarious reaction parameters such as the particular reactants, solventsand quantities used, those of ordinary skill in the art can readilydetermine suitable reaction conditions using routine optimizationprocedures.

Additionally, as will be apparent to those skilled in the art,conventional protecting groups may be necessary or desired to preventcertain functional groups from undergoing undesired reactions. Thechoice of a suitable protecting group for a particular functional groupas well as suitable conditions and reagents for protection anddeprotection of such functional groups are well-known in the art.Protecting groups other than those illustrated in the proceduresdescribed herein may be used, if desired. For example, numerousprotecting groups, and their introduction and removal, are described inT. W. Greene and G. M. Wuts, Protecting Groups in Organic Synthesis,Fourth Edition, Wiley, New York, 2006, and references cited therein.

Carboxy-protecting groups are suitable for preventing undesiredreactions at a carboxy group, and examples include, but are not limitedto, methyl, ethyl, t-butyl, benzyl (Bn), p-methoxybenzyl (PMB),9-fluorenylmethyl (Fm), trimethylsilyl (TMS), t-butyldimethylsilyl(TBDMS), diphenylmethyl (benzhydryl, DPM) and the like. Amino-protectinggroups are suitable for preventing undesired reactions at an aminogroup, and examples include, but are not limited to, t-butoxycarbonyl(BOC), trityl (Tr), benzyloxycarbonyl (Cbz), 9-fluorenylmethoxycarbonyl(Fmoc), formyl, trimethylsilyl (TMS), t-butyldimethylsilyl (TBDMS), andthe like. Hydroxyl-protecting groups are suitable for preventingundesired reactions at a hydroxyl group, and examples include, but arenot limited to C₁₋₆alkyls, silyl groups including triC₁₋₆alkylsilylgroups, such as trimethylsilyl (TMS), triethylsilyl (TES), andtert-butyldimethylsilyl (TBDMS); esters (acyl groups) includingC₁₋₆alkanoyl groups, such as formyl, acetyl, and pivaloyl, and aromaticacyl groups such as benzoyl; arylmethyl groups such as benzyl (Bn),p-methoxybenzyl (PMB), 9-fluorenylmethyl (Fm), and diphenylmethyl(benzhydryl, DPM); and the like.

Standard deprotection techniques and reagents are used to remove theprotecting groups, and may vary depending upon which group is used. Forexample, sodium or lithium hydroxide is commonly used when thecarboxy-protecting group is methyl, an acid such as TFA or HCl iscommonly used when the carboxy-protecting group is ethyl or t-butyl, andH₂/Pd/C may be used when the carboxy-protecting group is benzyl. A BOCamino-protecting group can be removed using an acidic reagent such asTFA in DCM or HCl in 1,4-dioxane, while a Cbz amino-protecting group canbe removed by employing catalytic hydrogenation conditions such as H₂ (1atm) and 10% Pd/C in an alcoholic solvent (“H₂/Pd/C”). H₂/Pd/C iscommonly used when the hydroxyl-protecting group is benzyl, while NaOHis commonly used when the hydroxyl-protecting group is an acyl group.

Suitable bases for use in these schemes include, by way of illustrationand not limitation, potassium carbonate, calcium carbonate, sodiumcarbonate, triethylamine, pyridine, 1,8-diazabicyclo-[5.4.0]undec-7-ene(DBU), N,N-diisopropylethylamine (DIPEA), 4-methylmorpholine, sodiumhydroxide, potassium hydroxide, potassium t-butoxide, and metalhydrides.

Suitable inert diluents or solvents for use in these schemes include, byway of illustration and not limitation, tetrahydrofuran (THF),acetonitrile (MeCN), N,N-dimethylformamide (DMF), N,N-dimethylacetamide(DMA), dimethyl sulfoxide (DMSO), toluene, dichloromethane (DCM),chloroform (CHCl₃), carbon tetrachloride (CCl₄), 1,4-dioxane, methanol,ethanol, water, and the like.

Suitable carboxylic acid/amine coupling reagents includebenzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate(BOP), benzotriazol-1-yloxytripyrrolidinophosphonium hexafluorophosphate(PyBOP), N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uroniumhexafluorophosphate (HATU), 1,3-dicyclohexylcarbodiimide (DCC),N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide (EDCI),carbonyldiimidazole (CDI), 1-hydroxybenzotriazole (HOBt), and the like.Coupling reactions are conducted in an inert diluent in the presence ofa base such as DIPEA, and are performed under conventional amidebond-forming conditions.

All reactions are typically conducted at a temperature within the rangeof about −78 C to 100° C., for example at room temperature. Reactionsmay be monitored by use of thin layer chromatography (TLC), highperformance liquid chromatography (HPLC), and/or LCMS until completion.Reactions may be complete in minutes, or may take hours, typically from1-2 hours and up to 48 hours. Upon completion, the resulting mixture orreaction product may be further treated in order to obtain the desiredproduct. For example, the resulting mixture or reaction product may besubjected to one or more of the following procedures: concentrating orpartitioning (for example, between EtOAc and water or between 5% THF inEtOAc and 1M phosphoric acid); extraction (for example, with EtOAc,CHCl₃, DCM, chloroform); washing (for example, with saturated aqueousNaCl, saturated aqueous NaHCO₃, Na₂CO₃ (5%), CHCl₃ or 1M NaOH); drying(for example, over MgSO₄, over Na₂SO₄, or in vacuo); filtering;crystallizing (for example, from EtOAc and hexanes); being concentrated(for example, in vacuo); and/or purification (e.g., silica gelchromatography, flash chromatography, preparative HPLC, reversephase-HPLC, or crystallization).

By way of illustration, Compounds of formula I, as well as their salts,can be prepared as shown in Scheme I:

The process comprises the step of coupling compound 1 with compound 2,where R¹-R⁶, X, a, and b are as defined for formula I, and P¹ is H or asuitable amino-protecting group, examples of which include,t-butoxycarbonyl, trityl, benzyloxycarbonyl, 9-fluorenylmethoxycarbonyl,formyl, trimethylsilyl, and t-butyldimethylsilyl. When P¹ is an aminoprotecting group, the process further comprises deprotecting thecompound of formula 1, before or in situ with the coupling step.

In instances where R¹ is a group such as —OCH₃ or OCH₂CH₃, the couplingstep may be followed by a deprotection step to provide a compound offormula I where R¹ is a group such as —OH. Thus, one method of preparingcompounds of the invention involves coupling compounds 1 and 2, with anoptional deprotection step to form a compound of formula I or apharmaceutically acceptable salt thereof.

Methods of preparing compound 1 are described in the Examples. Compound2 is generally commercially available or can be prepared usingprocedures that are known in the art.

Compounds of formula I, as well as their salts, can also be prepared asshown in Scheme II:

In the first step, compound 1 is coupled with compound 3 and compound 3is coupled to compound 4, where Y and Z react in situ to form the R³moiety. For example, when R³ is C(O)NR²²R²³, Y is —COOH and Z isHNR²²R²³. Alternately, compound 3 is first coupled to compound 4, andthe resulting compound is then coupled with compound 1. As with SchemeI, in instances where R¹ is a group such as —OCH₃ or OCH₂CH₃, thecoupling step may be followed by a deprotection step to provide acompound of formula I where R¹ is a group such as —OH. Thus, one methodof preparing compounds of the invention involves coupling compounds 1, 2and 3, with an optional deprotection step to form a compound of formulaI or a pharmaceutically acceptable salt thereof.

Compounds 3 and 4 are generally commercially available or can beprepared using procedures that are known in the art.

Compounds of formula I, as well as their salts, can also be prepared asshown in Scheme III:

Again, as with Schemes I and II, this is a standard coupling reactionbetween a compound of formula I, where R¹ is —OH and compound 5, toyield a compound of formula I, where R¹ is —NR⁸R⁹.

Certain intermediates described herein are believed to be novel andaccordingly, such compounds are provided as further aspects of theinvention including, for example, the compounds of formula 1, or a saltthereof:

where P¹ is H or an amino-protecting group selected fromt-butoxycarbonyl, trityl, benzyloxycarbonyl, 9-fluorenylmethoxycarbonyl,formyl, trimethylsilyl, and t-butyldimethylsilyl; and R¹, R², R⁵, R⁶, aand b are as defined for formula I. Another intermediate of theinvention has formula 6 or a salt thereof:

where R^(1P) is selected from —O—P³, —NHP², and —NH(O—P⁴); where P² isan amino-protecting group selected from t-butoxycarbonyl, trityl,benzyloxycarbonyl, 9-fluorenylmethoxycarbonyl, formyl, trimethylsilyl,and t-butyldimethylsilyl; P³ is a carboxy-protecting group selected frommethyl, ethyl, t-butyl, benzyl, p-methoxybenzyl, 9-fluorenylmethyl,trimethylsilyl, t-butyldimethylsilyl, and diphenylmethyl; P⁴ is ahydroxyl-protecting group selected from —C₁₋₆allyl, triC₁₋₆alkylsilyl,—C₁₋₆alkanoyl, benzoyl, benzyl, p-methoxybenzyl, 9-fluorenylmethyl, anddiphenylmethyl; and R², R³, R⁴, R⁵, R⁶, a, b, and X are as defined forformula I. Another intermediate of the invention has formula 7 or a saltthereof:

where R^(3P) is selected from —C₀₋₅alkylene-O—P⁴, —C₀₋₁alkylene-COO—P³,and phenyl substituted with —O—P⁴; P³ is a carboxy-protecting groupselected from methyl, ethyl, t-butyl, benzyl, p-methoxybenzyl,9-fluorenylmethyl, trimethylsilyl, t-butyldimethylsilyl, anddiphenylmethyl; P⁴ is a hydroxyl-protecting group selected from—C₁₋₆allyl, triC₁₋₆alkylsilyl, —C₁₋₆alkanoyl, benzoyl, benzyl,p-methoxybenzyl, 9-fluorenylmethyl, and diphenylmethyl; and R¹, R², R⁴,R⁵, R⁶, a, b, and X are as defined for formula I. Still anotherintermediate of the invention has formula 8 or a salt thereof:

where R^(4P) is selected from —O—P⁴; —C₁₋₂alkylene-COO—P³; and phenyl orbenzyl substituted with —COO—P³; P³ is a carboxy-protecting groupselected from methyl, ethyl, t-butyl, benzyl, p-methoxybenzyl,9-fluorenylmethyl, trimethylsilyl, t-butyldimethylsilyl, anddiphenylmethyl; P⁴ is a hydroxyl-protecting group selected from—C₁₋₆allyl, triC₁₋₆alkylsilyl, —C₁₋₆alkanoyl, benzoyl, benzyl,p-methoxybenzyl, 9-fluorenylmethyl, and diphenylmethyl; and R¹, R², R³,R⁵, R⁶, a, b, and X are as defined for formula I. Yet anotherintermediate of the invention has formula 9 or a salt thereof:

where R^(3P) is selected from —C₀₋₅alkylene-O—P⁴, —C₀₋₁alkylene-COO—P³,and phenyl substituted with —O—P⁴; R^(4P) is selected from —O—P⁴;—C₁₋₂allylene-COO—P³; and phenyl or benzyl substituted with —COO—P³; P³is a carboxy-protecting group selected from methyl, ethyl, t-butyl,benzyl, p-methoxybenzyl, 9-fluorenylmethyl, trimethylsilyl,t-butyldimethylsilyl, and diphenylmethyl; P⁴ is a hydroxyl-protectinggroup selected from —C₁₋₆allyl, triC₁₋₆alkylsilyl, —C₁₋₆alkanoyl,benzoyl, benzyl, p-methoxybenzyl, 9-fluorenylmethyl, and diphenylmethyl;and R¹, R², R⁵, R⁶, a, b, and X are as defined for formula I. Thus,another method of preparing compounds of the invention involvesdeprotecting a compound of formula 1, 6, 7, 8, 9, or a salt thereof.

Further details regarding specific reaction conditions and otherprocedures for preparing representative compounds of the invention orintermediates thereof are described in the Examples set forth below.

UTILITY

Compounds of the invention possess neprilysin (NEP) inhibition activity,that is, the compounds are able to inhibit enzyme-catalytic activity. Inanother embodiment, the compounds do not exhibit significant inhibitoryactivity of the angiotensin-converting enzyme. Compounds of formula Imay be active drugs as well as prodrugs. Thus, when discussing theactivity of compounds of the invention, it is understood that any suchprodrugs have the expected activity once metabolized.

One measure of the ability of a compound to inhibit NEP activity is theinhibition constant (pK_(i)). The pK_(i) value is the negative logarithmto base 10 of the dissociation constant (K_(i)), which is typicallyreported in molar units. Compounds of the invention of particularinterest are those having a pK_(i) at NEP greater than or equal to 6.0,particularly those having a pK_(i) greater than or equal to 7.0, andeven more particularly those having a pK_(i) greater than or equal to8.0. In one embodiment, compounds of interest have a pK_(i) in the rangeof 6.0-6.9; in another embodiment, compounds of interest have a pK_(i)in the range of 7.0-7.9; in yet another embodiment, compounds ofinterest have a pK_(i) in the range of 8.0-8.9; and in still anotherembodiment, compounds of interest have a pK_(i) in the range of greaterthan or equal to 9.0. Such values can be determined by techniques thatare well know in the art, as well as in the assays described herein.

Another measure of the ability of a compound to inhibit NEP activity isthe apparent inhibition constant (IC₅₀), which is the molarconcentration of compound that results in half-maximal inhibition ofsubstrate conversion by the NEP enzyme. The pIC₅₀ value is the negativelogarithm to base 10 of the IC₅₀. Compounds of the invention that are ofparticular interest, include those that exhibit a pIC₅₀ for NEP greaterthan or equal to about 5.0. Compounds of interest also include thosehaving a pIC₅₀ for NEP ≧about 6.0 or a pIC₅₀ for NEP ≧about 7.0. Inanother embodiment, compounds of interest have a pIC₅₀ for NEP withinthe range of about 7.0-11.0; and in another embodiment, within the rangeof about 8.0-11.0, such as within the range of about 8.0-10.0.

It is noted that in some cases, compounds of the invention may possessweak NEP inhibition activity. In such cases, those of skill in the artwill recognize that these compounds still have utility as researchtools.

Exemplary assays to determine properties of compounds of the invention,such as the NEP inhibiting activity, are described in the Examples andinclude by way of illustration and not limitation, assays that measureNEP inhibition (described in Assay 1). Useful secondary assays includeassays to measure ACE inhibition (also described in Assay 1) andaminopeptidase P (APP) inhibition (described in Sulpizio et al. (2005)JPET 315:1306-1313). A pharmacodynamic assay to assess the in vivoinhibitory potencies for ACE and NEP in anesthetized rats is describedin Assay 2 (see also Seymour et al. (1985) Hypertension 7(Suppl41-35-1-42 and Wigle et al. (1992) Can. J. Physiol. Pharmacol.70:1525-1528), where ACE inhibition is measured as the percentinhibition of the angiotensin I pressor response and NEP inhibition ismeasured as increased urinary cyclic guanosine 3′,5′-monophosphate(cGMP) output.

There are many in vivo assays that can be used to ascertain furtherutilities of the compounds of the invention. The conscious spontaneouslyhypertensive rat (SHR) model is a renin dependent hypertension model,and is described in Assay 3. See also Intengan et al. (1999) Circulation100(22):2267-2275 and Badyal et al. (2003) Indian Journal ofPharmacology 35:349-362. The conscious desoxycorticosterone acetate-salt(DOCA-salt) rat model is a volume dependent hypertension model that isuseful for measuring NEP activity, and is described in Assay 4. See alsoTrapani et al. (1989) J. Cardiovasc. Pharmacol. 14:419-424, Intengan etal. (1999) Hypertension 34(4):907-913, and Badyal et al. (2003) supra).The DOCA-salt model is particularly useful for evaluating the ability ofa test compound to reduce blood pressure as well as to measure a testcompound's ability to prevent or delay a rise in blood pressure. TheDahl salt-sensitive (DSS) hypertensive rat model is a model ofhypertension that is sensitive to dietary salt (NaCl), and is describedin Assay 5. See also Rapp (1982) Hypertension 4:753-763. The ratmonocrotaline model of pulmonary arterial hypertension described, forexample, in Kato et al. (2008) J. Cardiovasc. Pharmacol. 51(1):18-23, isa reliable predictor of clinical efficacy for the treatment of pulmonaryarterial hypertension. Heart failure animal models include the DSS ratmodel for heart failure and the aorto-caval fistula model (AV shunt),the latter of which is described, for example, in Norling et al. (1996)J. Amer. Soc. Nephrol. 7:1038-1044. Other animal models, such as the hotplate, tail-flick and formalin tests, can be used to measure theanalgesic properties of compounds of the invention, as well as thespinal nerve ligation (SNL) model of neuropathic pain. See, for example,Malmberg et al. (1999) Current Protocols in Neuroscience 8.9.1-8.9.15.

Compounds of the invention are expected to inhibit the NEP enzyme in anyof the assays listed above, or assays of a similar nature. Thus, theaforementioned assays are useful in determining the therapeutic utilityof compounds of the invention, for example, their utility asantihypertensive agents or antidiarrheal agents. Other properties andutilities of compounds of the invention can be demonstrated using otherin vitro and in vivo assays well-known to those skilled in the art.Compounds of formula I may be active drugs as well as prodrugs. Thus,when discussing the activity of compounds of the invention, it isunderstood that any such prodrugs may not exhibit the expected activityin an assay, but are expected to exhibit the desired activity oncemetabolized.

Compounds of the invention are expected to be useful for the treatmentand/or prevention of medical conditions responsive to NEP inhibition.Thus it is expected that patients suffering from a disease or disorderthat is treated by inhibiting the NEP enzyme or by increasing the levelsof its peptide substrates, can be treated by administering atherapeutically effective amount of a compound of the invention. Forexample, by inhibiting NEP, the compounds are expected to potentiate thebiological effects of endogenous peptides that are metabolized by NEP,such as the natriuretic peptides, bombesin, bradykinins, calcitonin,endothelins, enkephalins, neurotensin, substance P and vasoactiveintestinal peptide. Thus, these compounds are expected to have otherphysiological actions, for example, on the renal, central nervous,reproductive and gastrointestinal systems.

In one embodiment of the invention, patients suffering from a disease ordisorder that is treated by inhibiting the NEP enzyme, are treated byadministering a compound of the invention that is in its active form,i.e., a compound of formula I where R¹ is selected from —OR⁷ and —NR⁸R⁹,R⁷ is H, R⁸ is H or —OH, R⁹ is H, and R²-R⁶, a, b, and X are as definedfor formula I.

In another embodiment, patients are treated by administering a compoundthat is metabolized in vitro to form a compound of formula I where R¹ isselected from —OR⁷ and —NR⁸R⁹, R⁷ is H, R⁸ is H or —OH, R⁹ is H, andR²-R⁶, a, b, and X are as defined for formula I.

In another embodiment, patients are treated by administering a compoundof the invention that is in its prodrug form at the R¹ group, i.e., acompound of formula I where:

R¹ is —OR⁷; and R⁷ is selected from —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R¹⁰, —C₁₋₆alkylene-NR¹²R¹³, —C₁₋₆alkylene-C(O)R³¹,—C₀₋₆alkylenemorpholinyl, —C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

or

R¹ is —NR⁸R⁹; R⁸ is selected from —OC(O)R¹⁴, —CH₂COOH, —O-benzyl,pyridyl, and —OC(S)NR¹⁵R¹⁶; and R⁹ is H; or

R¹ is —NR⁸R⁹; R⁸ is selected from —OC(O)R¹⁴, —CH₂COOH, —O-benzyl,pyridyl, and —OC(S)NR¹⁵R¹⁶; and R⁹ is —C₁₋₆alkyl or —C(O)R¹⁷;

R¹ is —NR⁸R⁹; R⁸ is selected from H or —OH; and R⁹ is selected from—C₁₋₆alkyl, and —C(O)R¹⁷;

R¹ is —OR⁷ and R² is taken together with R⁷ to form —CR¹⁸R¹⁹—; or

R¹ is —NR⁸R⁹ and R² is taken together with R⁸ to form —C(O)—;

and R¹⁰, R¹²-R¹², R³¹, R³², R³-R⁶, a, b, and X are as defined forformula I.

Cardiovascular Diseases

By potentiating the effects of vasoactive peptides like the natriureticpeptides and bradykinin, compounds of the invention are expected to findutility in treating and/or preventing medical conditions such ascardiovascular diseases. See, for example, Rogues et al. (1993)Pharmacol. Rev. 45:87-146 and Dempsey et al. (2009) Amer. J. ofPathology 174(3):782-796. Cardiovascular diseases of particular interestinclude hypertension and heart failure. Hypertension includes, by way ofillustration and not limitation: primary hypertension, which is alsoreferred to as essential hypertension or idiopathic hypertension;secondary hypertension; hypertension with accompanying renal disease;severe hypertension with or without accompanying renal disease;pulmonary hypertension, including pulmonary arterial hypertension; andresistant hypertension. Heart failure includes, by way of illustrationand not limitation: congestive heart failure; acute heart failure;chronic heart failure, for example with reduced left ventricularejection fraction (also referred to as systolic heart failure) or withpreserved left ventricular ejection fraction (also referred to asdiastolic heart failure); and acute and chronic decompensated heartfailure, with or without accompanying renal disease. Thus, oneembodiment of the invention relates to a method for treatinghypertension, particularly primary hypertension or pulmonary arterialhypertension, comprising administering to a patient a therapeuticallyeffective amount of a compound of the invention.

For treatment of primary hypertension, the therapeutically effectiveamount is typically the amount that is sufficient to lower the patient'sblood pressure. This would include both mild-to-moderate hypertensionand severe hypertension. When used to treat hypertension, the compoundmay be administered in combination with other therapeutic agents such asaldosterone antagonists, angiotensin-converting enzyme inhibitors anddual-acting angiotensin-converting enzyme/neprilysin inhibitors,angiotensin-converting enzyme 2 (ACE2) activators and stimulators,angiotensin-II vaccines, anti-diabetic agents, anti-lipid agents,anti-thrombotic agents, AT₁ receptor antagonists and dual-acting AT₁receptor antagonist/neprilysin inhibitors, β₁-adrenergic receptorantagonists, dual-acting β-adrenergic receptor antagonist/α₁-receptorantagonists, calcium channel blockers, diuretics, endothelin receptorantagonists, endothelin converting enzyme inhibitors, neprilysininhibitors, natriuretic peptides and their analogs, natriuretic peptideclearance receptor antagonists, nitric oxide donors, non-steroidalanti-inflammatory agents, phosphodiesterase inhibitors (specificallyPDE-V inhibitors), prostaglandin receptor agonists, renin inhibitors,soluble guanylate cyclase stimulators and activators, and combinationsthereof. In one particular embodiment of the invention, a compound ofthe invention is combined with an AT₁ receptor antagonist, a diuretic, acalcium channel blocker, or a combination thereof, and used to treatprimary hypertension. In another particular embodiment of the invention,a compound of the invention is combined with an AT₁ receptor antagonist,and used to treat hypertension with accompanying renal disease.

For treatment of pulmonary arterial hypertension, the therapeuticallyeffective amount is typically the amount that is sufficient to lower thepulmonary vascular resistance. Other goals of therapy are to improve apatient's exercise capacity. For example, in a clinical setting, thetherapeutically effective amount can be the amount that improves apatient's ability to walk comfortably for a period of 6 minutes(covering a distance of approximately 20-40 meters). When used to treatpulmonary arterial hypertension the compound may be administered incombination with other therapeutic agents such as a-adrenergicantagonists, β₁-adrenergic receptor antagonists, β₂-adrenergic receptoragonists, angiotensin-converting enzyme inhibitors, anticoagulants,calcium channel blockers, diuretics, endothelin receptor antagonists,PDE-V inhibitors, prostaglandin analogs, selective serotonin reuptakeinhibitors, and combinations thereof. In one particular embodiment ofthe invention, a compound of the invention is combined with a PDE-Vinhibitor or a selective serotonin reuptake inhibitor and used to treatpulmonary arterial hypertension.

Another embodiment of the invention relates to a method for treatingheart failure, in particular congestive heart failure (including bothsystolic and diastolic congestive heart failure), comprisingadministering to a patient a therapeutically effective amount of acompound of the invention. Typically, the therapeutically effectiveamount is the amount that is sufficient to lower blood pressure and/orimprove renal functions. In a clinical setting, the therapeuticallyeffective amount can be the amount that is sufficient to improve cardiachemodynamics, like for instance reduction in wedge pressure, rightatrial pressure, filling pressure, and vascular resistance. In oneembodiment, the compound is administered as an intravenous dosage form.When used to treat heart failure, the compound may be administered incombination with other therapeutic agents such as adenosine receptorantagonists, advanced glycation end product breakers, aldosteroneantagonists, AT₁ receptor antagonists, β₁-adrenergic receptorantagonists, dual-acting β-adrenergic receptor antagonist/α₁-receptorantagonists, chymase inhibitors, digoxin, diuretics, endothelinconverting enzyme (ECE) inhibitors, endothelin receptor antagonists,natriuretic peptides and their analogs, natriuretic peptide clearancereceptor antagonists, nitric oxide donors, prostaglandin analogs, PDE-Vinhibitors, soluble guanylate cyclase activators and stimulators, andvasopressin receptor antagonists. In one particular embodiment of theinvention, a compound of the invention is combined with an aldosteroneantagonist, a β₁-adrenergic receptor antagonist, an AT₁ receptorantagonist, or a diuretic, and used to treat congestive heart failure.

Diarrhea

As NEP inhibitors, compounds of the invention are expected to inhibitthe degradation of endogenous enkephalins and thus such compounds mayalso find utility for the treatment of diarrhea, including infectiousand secretory/watery diarrhea. See, for example, Baumer et al. (1992)Gut 33:753-758; Farthing (2006) Digestive Diseases 24:47-58; andMarØais-Collado (1987) Eur. J. Pharmacol. 144(2):125-132. When used totreat diarrhea, compounds of the invention may be combined with one ormore additional antidiarrheal treatments.

Renal Diseases

By potentiating the effects of vasoactive peptides like the natriureticpeptides and bradykinin, compounds of the invention are expected toenhance renal function (see Chen et al. (1999) Circulation100:2443-2448; Lipkin et al. (1997) Kidney Int. 52:792-801; and Dussauleet al. (1993) Clin. Sci. 84:31-39) and find utility in treating and/orpreventing renal diseases. Renal diseases of particular interest includediabetic nephropathy, chronic kidney disease, proteinuria, andparticularly acute kidney injury or acute renal failure (see Sharkovskaet al. (2011) Clin. Lab. 57:507-515 and Newaz et al. (2010) RenalFailure 32:384-390). When used to treat renal disease, the compound maybe administered in combination with other therapeutic agents such asangiotensin-converting enzyme inhibitors, AT₁ receptor antagonists, anddiuretics.

Preventative Therapy

By potentiating the effects of the natriuretic peptides, compounds ofthe invention are also expected to be useful in preventative therapy,due to the antihypertrophic and antifibrotic effects of the natriureticpeptides (see Potter et al. (2009) Handbook of Experimental Pharmacology191:341-366), for example in preventing the progression of cardiacinsufficiency after myocardial infarction, preventing arterialrestenosis after angioplasty, preventing thickening of blood vesselwalls after vascular operations, preventing atherosclerosis, andpreventing diabetic angiopathy.

Glaucoma

By potentiating the effects of the natriuretic peptides, compounds ofthe invention are expected to be useful to treat glaucoma. See, forexample, Diestelhorst et al. (1989) International Ophthalmology12:99-101. When used to treat glaucoma, compounds of the invention maybe combined with one or more additional anti-glaucoma agents.

Pain Relief

As NEP inhibitors, compounds of the invention are expected to inhibitthe degradation of endogenous enkephalins and thus such compounds mayalso find utility as analgesics. See, for example, Rogues et al. (1980)Nature 288:286-288 and Thanawala et al. (2008) Current Drug Targets9:887-894. When used to treat pain, compounds of the invention may becombined with one or more additional antinociceptive drugs such asaminopeptidase N or dipeptidyl peptidase III inhibitors, non-steroidalanti-inflammatory agents, monoamine reuptake inhibitors, musclerelaxants, NMDA receptor antagonists, opioid receptor agonists,5-HT_(1D) serotonin receptor agonists, and tricyclic antidepressants.

Other Utilities

Due to their NEP inhibition properties, compounds of the invention arealso expected to be useful as antitussive agents, as well as findutility in the treatment of portal hypertension associated with livercirrhosis (see Sansoe et al. (2005) J. Hepatol. 43:791-798), cancer (seeVesely (2005) J. Investigative Med. 53:360-365), depression (see Nobleet al. (2007) Exp. Opin. Ther. Targets 11:145-159), menstrual disorders,preterm labor, pre-eclampsia, endometriosis, reproductive disorders (forexample, male and female infertility, polycystic ovarian syndrome,implantation failure), and male and female sexual dysfunction, includingmale erectile dysfunction and female sexual arousal disorder. Morespecifically, the compounds of the invention are expected to be usefulin treating female sexual dysfunction (see Pryde et al. (2006) J. Med.Chem. 49:4409-4424), which is often defined as a female patient'sdifficulty or inability to find satisfaction in sexual expression. Thiscovers a variety of diverse female sexual disorders including, by way ofillustration and not limitation, hypoactive sexual desire disorder,sexual arousal disorder, orgasmic disorder and sexual pain disorder.When used to treat such disorders, especially female sexual dysfunction,compounds of the invention may be combined with one or more of thefollowing secondary agents: PDE-V inhibitors, dopamine agonists,estrogen receptor agonists and/or antagonists, androgens, and estrogens.Due to their NEP inhibition properties, compounds of the invention arealso expected to have anti-inflammatory properties, and are expected tohave utility as such, particularly when used in combination withstatins.

Recent studies suggest that NEP plays a role in regulating nervefunction in insulin-deficient diabetes and diet induced obesity. Coppeyet al. (2011) Neuropharmacology 60:259-266. Therefore, due to their NEPinhibition properties, compounds of the invention are also expected tobe useful in providing protection from nerve impairment caused bydiabetes or diet induced obesity.

The amount of the compound of the invention administered per dose or thetotal amount administered per day may be predetermined or it may bedetermined on an individual patient basis by taking into considerationnumerous factors, including the nature and severity of the patient'scondition, the condition being treated, the age, weight, and generalhealth of the patient, the tolerance of the patient to the active agent,the route of administration, pharmacological considerations such as theactivity, efficacy, pharmacokinetics and toxicology profiles of thecompound and any secondary agents being administered, and the like.Treatment of a patient suffering from a disease or medical condition(such as hypertension) can begin with a predetermined dosage or a dosagedetermined by the treating physician, and will continue for a period oftime necessary to prevent, ameliorate, suppress, or alleviate thesymptoms of the disease or medical condition. Patients undergoing suchtreatment will typically be monitored on a routine basis to determinethe effectiveness of therapy. For example, in treating hypertension,blood pressure measurements may be used to determine the effectivenessof treatment. Similar indicators for other diseases and conditionsdescribed herein, are well known and are readily available to thetreating physician. Continuous monitoring by the physician will insurethat the optimal amount of the compound of the invention will beadministered at any given time, as well as facilitating thedetermination of the duration of treatment. This is of particular valuewhen secondary agents are also being administered, as their selection,dosage, and duration of therapy may also require adjustment. In thisway, the treatment regimen and dosing schedule can be adjusted over thecourse of therapy so that the lowest amount of active agent thatexhibits the desired effectiveness is administered and, further, thatadministration is continued only so long as is necessary to successfullytreat the disease or medical condition.

Research Tools

Since compounds of the invention possess NEP enzyme inhibition activity,such compounds are also useful as research tools for investigating orstudying biological systems or samples having a NEP enzyme, for exampleto study diseases where the NEP enzyme or its peptide substrates plays arole. Any suitable biological system or sample having a NEP enzyme maybe employed in such studies which may be conducted either in vitro or invivo. Representative biological systems or samples suitable for suchstudies include, but are not limited to, cells, cellular extracts,plasma membranes, tissue samples, isolated organs, mammals (such asmice, rats, guinea pigs, rabbits, dogs, pigs, humans, and so forth), andthe like, with mammals being of particular interest. In one particularembodiment of the invention, NEP enzyme activity in a mammal isinhibited by administering a NEP-inhibiting amount of a compound of theinvention. Compounds of the invention can also be used as research toolsby conducting biological assays using such compounds.

When used as a research tool, a biological system or sample comprising aNEP enzyme is typically contacted with a NEP enzyme-inhibiting amount ofa compound of the invention. After the biological system or sample isexposed to the compound, the effects of inhibiting the NEP enzyme aredetermined using conventional procedures and equipment, such as bymeasuring receptor binding in a binding assay or measuringligand-mediated changes in a functional assay. Exposure encompassescontacting cells or tissue with the compound, administering the compoundto a mammal, for example by i.p., p.o, i.v., s.c., or inhaledadministration, and so forth. This determining step can involvemeasuring a response (a quantitative analysis) or can involve making anobservation (a qualitative analysis). Measuring a response involves, forexample, determining the effects of the compound on the biologicalsystem or sample using conventional procedures and equipment, such asenzyme activity assays and measuring enzyme substrate or productmediated changes in functional assays. The assay results can be used todetermine the activity level as well as the amount of compound necessaryto achieve the desired result, that is, a NEP enzyme-inhibiting amount.Typically, the determining step will involve determining the effects ofinhibiting the NEP enzyme.

Additionally, compounds of the invention can be used as research toolsfor evaluating other chemical compounds, and thus are also useful inscreening assays to discover, for example, new compounds havingNEP-inhibiting activity. In this manner, a compound of the invention isused as a standard in an assay to allow comparison of the resultsobtained with a test compound and with compounds of the invention toidentify those test compounds that have about equal or superioractivity, if any. For example, pK_(i) data for a test compound or agroup of test compounds is compared to the pK_(i) data for a compound ofthe invention to identify those test compounds that have the desiredproperties, for example, test compounds having a pK_(i) value aboutequal or superior to a compound of the invention, if any. This aspect ofthe invention includes, as separate embodiments, both the generation ofcomparison data (using the appropriate assays) and the analysis of testdata to identify test compounds of interest. Thus, a test compound canbe evaluated in a biological assay, by a method comprising the steps of:(a) conducting a biological assay with a test compound to provide afirst assay value; (b) conducting the biological assay with a compoundof the invention to provide a second assay value; wherein step (a) isconducted either before, after or concurrently with step (b); and (c)comparing the first assay value from step (a) with the second assayvalue from step (b). Exemplary biological assays include a NEP enzymeinhibition assay.

Pharmaceutical Compositions and Formulations

Compounds of the invention are typically administered to a patient inthe form of a pharmaceutical composition or formulation. Suchpharmaceutical compositions may be administered to the patient by anyacceptable route of administration including, but not limited to, oral,rectal, vaginal, nasal, inhaled, topical (including transdermal),ocular, and parenteral modes of administration. Further, the compoundsof the invention may be administered, for example orally, in multipledoses per day (for example, two, three, or four times daily), in asingle daily dose or a single weekly dose. It will be understood thatany form of the compounds of the invention, (that is, free base, freeacid, pharmaceutically acceptable salt, solvate, etc.) that is suitablefor the particular mode of administration can be used in thepharmaceutical compositions discussed herein.

Accordingly, in one embodiment, the invention relates to apharmaceutical composition comprising a pharmaceutically acceptablecarrier and a compound of the invention. The compositions may containother therapeutic and/or formulating agents if desired. When discussingcompositions, the “compound of the invention” may also be referred toherein as the “active agent,” to distinguish it from other components ofthe formulation, such as the carrier. Thus, it is understood that theterm “active agent” includes compounds of formula I as well aspharmaceutically acceptable salts, solvates and prodrugs of thatcompound.

The pharmaceutical compositions of the invention typically contain atherapeutically effective amount of a compound of the invention. Thoseskilled in the art will recognize, however, that a pharmaceuticalcomposition may contain more than a therapeutically effective amount,such as in bulk compositions, or less than a therapeutically effectiveamount, that is, individual unit doses designed for multipleadministration to achieve a therapeutically effective amount. Typically,the composition will contain from about 0.01-95 wt % of active agent,including, from about 0.01-30 wt %, such as from about 0.01-10 wt %,with the actual amount depending upon the formulation itself, the routeof administration, the frequency of dosing, and so forth. In oneembodiment, a composition suitable for an oral dosage form, for example,may contain about 5-70 wt %, or from about 10-60 wt % of active agent.

Any conventional carrier or excipient may be used in the pharmaceuticalcompositions of the invention. The choice of a particular carrier orexcipient, or combinations of carriers or excipients, will depend on themode of administration being used to treat a particular patient or typeof medical condition or disease state. In this regard, the preparationof a suitable composition for a particular mode of administration iswell within the scope of those skilled in the pharmaceutical arts.Additionally, carriers or excipients used in such compositions arecommercially available. By way of further illustration, conventionalformulation techniques are described in Remington: The Science andPractice of Pharmacy, 20^(th) Edition, Lippincott Williams & White,Baltimore, Md. (2000); and H. C. Ansel et al., Pharmaceutical DosageForms and Drug Delivery Systems, 7^(th) Edition, Lippincott Williams &White, Baltimore, Md. (1999).

Representative examples of materials which can serve as pharmaceuticallyacceptable carriers include, but are not limited to, the following:sugars, such as lactose, glucose and sucrose; starches, such as cornstarch and potato starch; cellulose, such as microcrystalline cellulose,and its derivatives, such as sodium carboxymethyl cellulose, ethylcellulose and cellulose acetate; powdered tragacanth; malt; gelatin;talc; excipients, such as cocoa butter and suppository waxes; oils, suchas peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil,corn oil and soybean oil; glycols, such as propylene glycol; polyols,such as glycerin, sorbitol, mannitol and polyethylene glycol; esters,such as ethyl oleate and ethyl laurate; agar; buffering agents, such asmagnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-freewater; isotonic saline; Ringer's solution; ethyl alcohol; phosphatebuffer solutions; compressed propellant gases, such aschlorofluorocarbons and hydrofluorocarbons; and other non-toxiccompatible substances employed in pharmaceutical compositions.

Pharmaceutical compositions are typically prepared by thoroughly andintimately mixing or blending the active agent with a pharmaceuticallyacceptable carrier and one or more optional ingredients. The resultinguniformly blended mixture may then be shaped or loaded into tablets,capsules, pills, canisters, cartridges, dispensers and the like usingconventional procedures and equipment.

In one embodiment, the pharmaceutical compositions are suitable for oraladministration. Suitable compositions for oral administration may be inthe form of capsules, tablets, pills, lozenges, cachets, dragees,powders, granules; solutions or suspensions in an aqueous or non-aqueousliquid; oil-in-water or water-in-oil liquid emulsions; elixirs orsyrups; and the like; each containing a predetermined amount of theactive agent.

When intended for oral administration in a solid dosage form (capsules,tablets, pills and the like), the composition will typically comprisethe active agent and one or more pharmaceutically acceptable carriers,such as sodium citrate or dicalcium phosphate. Solid dosage forms mayalso comprise: fillers or extenders, such as starches, microcrystallinecellulose, lactose, sucrose, glucose, mannitol, and/or silicic acid;binders, such as carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidone, sucrose and/or acacia; humectants, such as glycerol;disintegrating agents, such as agar-agar, calcium carbonate, potato ortapioca starch, alginic acid, certain silicates, and/or sodiumcarbonate; solution retarding agents, such as paraffin; absorptionaccelerators, such as quaternary ammonium compounds; wetting agents,such as cetyl alcohol and/or glycerol monostearate; absorbents, such askaolin and/or bentonite clay; lubricants, such as talc, calciumstearate, magnesium stearate, solid polyethylene glycols, sodium laurylsulfate, and/or mixtures thereof; coloring agents; and buffering agents.

Release agents, wetting agents, coating agents, sweetening, flavoringand perfuming agents, preservatives and antioxidants may also be presentin the pharmaceutical compositions. Exemplary coating agents fortablets, capsules, pills and like, include those used for entericcoatings, such as cellulose acetate phthalate, polyvinyl acetatephthalate, hydroxypropyl methylcellulose phthalate, methacrylicacid-methacrylic acid ester copolymers, cellulose acetate trimellitate,carboxymethyl ethyl cellulose, hydroxypropyl methyl cellulose acetatesuccinate, and the like. Examples of pharmaceutically acceptableantioxidants include: water-soluble antioxidants, such as ascorbic acid,cysteine hydrochloride, sodium bisulfate, sodium metabisulfate sodiumsulfite and the like; oil-soluble antioxidants, such as ascorbylpalmitate, butylated hydroxyanisole, butylated hydroxytoluene, lecithin,propyl gallate, alpha-tocopherol, and the like; and metal-chelatingagents, such as citric acid, ethylenediamine tetraacetic acid, sorbitol,tartaric acid, phosphoric acid, and the like.

Compositions may also be formulated to provide slow or controlledrelease of the active agent using, by way of example, hydroxypropylmethyl cellulose in varying proportions or other polymer matrices,liposomes and/or microspheres. In addition, the pharmaceuticalcompositions of the invention may contain opacifying agents and may beformulated so that they release the active agent only, orpreferentially, in a certain portion of the gastrointestinal tract,optionally, in a delayed manner. Examples of embedding compositionswhich can be used include polymeric substances and waxes. The activeagent can also be in micro-encapsulated form, optionally with one ormore of the above-described excipients.

Suitable liquid dosage forms for oral administration include, by way ofillustration, pharmaceutically acceptable emulsions, microemulsions,solutions, suspensions, syrups and elixirs. Liquid dosage formstypically comprise the active agent and an inert diluent, such as, forexample, water or other solvents, solubilizing agents and emulsifiers,such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethylacetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butyleneglycol, oils (for example, cottonseed, groundnut, corn, germ, olive,castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethyleneglycols and fatty acid esters of sorbitan, and mixtures thereof.Suspensions may contain suspending agents such as, for example,ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitanesters, microcrystalline cellulose, aluminium metahydroxide, bentonite,agar-agar and tragacanth, and mixtures thereof.

When intended for oral administration, the pharmaceutical compositionsof the invention may be packaged in a unit dosage form. The term “unitdosage form” refers to a physically discrete unit suitable for dosing apatient, that is, each unit containing a predetermined quantity of theactive agent calculated to produce the desired therapeutic effect eitheralone or in combination with one or more additional units. For example,such unit dosage forms may be capsules, tablets, pills, and the like.

In another embodiment, the compositions of the invention are suitablefor inhaled administration, and will typically be in the form of anaerosol or a powder. Such compositions are generally administered usingwell-known delivery devices, such as a nebulizer, dry powder, ormetered-dose inhaler. Nebulizer devices produce a stream of highvelocity air that causes the composition to spray as a mist that iscarried into a patient's respiratory tract. An exemplary nebulizerformulation comprises the active agent dissolved in a carrier to form asolution, or micronized and combined with a carrier to form a suspensionof micronized particles of respirable size. Dry powder inhalersadminister the active agent as a free-flowing powder that is dispersedin a patient's air-stream during inspiration. An exemplary dry powderformulation comprises the active agent dry-blended with an excipientsuch as lactose, starch, mannitol, dextrose, polylactic acid,polylactide-co-glycolide, and combinations thereof. Metered-doseinhalers discharge a measured amount of the active agent usingcompressed propellant gas. An exemplary metered-dose formulationcomprises a solution or suspension of the active agent in a liquefiedpropellant, such as a chlorofluorocarbon or hydrofluoroalkane. Optionalcomponents of such formulations include co-solvents, such as ethanol orpentane, and surfactants, such as sorbitan trioleate, oleic acid,lecithin, glycerin, and sodium lauryl sulfate. Such compositions aretypically prepared by adding chilled or pressurized hydrofluoroalkane toa suitable container containing the active agent, ethanol (if present)and the surfactant (if present). To prepare a suspension, the activeagent is micronized and then combined with the propellant.Alternatively, a suspension formulation can be prepared by spray dryinga coating of surfactant on micronized particles of the active agent. Theformulation is then loaded into an aerosol canister, which forms aportion of the inhaler.

Compounds of the invention can also be administered parenterally (forexample, by subcutaneous, intravenous, intramuscular, or intraperitonealinjection). For such administration, the active agent is provided in asterile solution, suspension, or emulsion. Exemplary solvents forpreparing such formulations include water, saline, low molecular weightalcohols such as propylene glycol, polyethylene glycol, oils, gelatin,fatty acid esters such as ethyl oleate, and the like. Parenteralformulations may also contain one or more anti-oxidants, solubilizers,stabilizers, preservatives, wetting agents, emulsifiers, and dispersingagents. Surfactants, additional stabilizing agents or pH-adjustingagents (acids, bases or buffers) and anti-oxidants are particularlyuseful to provide stability to the formulation, for example, to minimizeor avoid hydrolysis of ester and amide linkages, or dimerization ofthiols that may be present in the compound. These formulations may berendered sterile by use of a sterile injectable medium, a sterilizingagent, filtration, irradiation, or heat. In one particular embodiment,the parenteral formulation comprises an aqueous cyclodextrin solution asthe pharmaceutically acceptable carrier. Suitable cyclodextrins includecyclic molecules containing six or more α-D-glucopyranose units linkedat the 1,4 positions by a linkages as in amylase, β-cyclodextrin orcycloheptaamylose. Exemplary cyclodextrins include cyclodextrinderivatives such as hydroxypropyl and sulfobutyl ether cyclodextrinssuch as hydroxypropyl-β-cyclodextrin and sulfobutyl etherβ-cyclodextrin. Exemplary buffers for such formulations includecarboxylic acid-based buffers such as citrate, lactate and maleatebuffer solutions.

Compounds of the invention can also be administered transdermally usingknown transdermal delivery systems and excipients. For example, thecompound can be admixed with permeation enhancers, such as propyleneglycol, polyethylene glycol monolaurate, azacycloalkan-2-ones and thelike, and incorporated into a patch or similar delivery system.Additional excipients including gelling agents, emulsifiers and buffers,may be used in such transdermal compositions if desired.

Secondary Agents

The compounds of the invention may be useful as the sole treatment of adisease or may be combined with one or more other therapeutic agents inorder to obtain the desired therapeutic effect. Thus, in one embodiment,pharmaceutical compositions of the invention contain other drugs thatare co-administered with a compound of the invention. For example, thecomposition may further comprise one or more drugs (also referred to as“secondary agents(s)”). Such therapeutic agents are well known in theart, and include adenosine receptor antagonists, a-adrenergic receptorantagonists, β₁-adrenergic receptor antagonists, β₂-adrenergic receptoragonists, dual-acting β-adrenergic receptor antagonist/α₁-receptorantagonists, advanced glycation end product breakers, aldosteroneantagonists, aldosterone synthase inhibitors, aminopeptidase Ninhibitors, androgens, angiotensin-converting enzyme inhibitors anddual-acting angiotensin-converting enzyme/neprilysin inhibitors,angiotensin-converting enzyme 2 activators and stimulators,angiotensin-II vaccines, anticoagulants, anti-diabetic agents,antidiarrheal agents, anti-glaucoma agents, anti-lipid agents,antinociceptive agents, anti-thrombotic agents, AT₁ receptor antagonistsand dual-acting AT₁ receptor antagonist/neprilysin inhibitors andmultifunctional angiotensin receptor blockers, bradykinin receptorantagonists, calcium channel blockers, chymase inhibitors, digoxin,diuretics, dopamine agonists, endothelin converting enzyme inhibitors,endothelin receptor antagonists, HMG-CoA reductase inhibitors,estrogens, estrogen receptor agonists and/or antagonists, monoaminereuptake inhibitors, muscle relaxants, natriuretic peptides and theiranalogs, natriuretic peptide clearance receptor antagonists, neprilysininhibitors, nitric oxide donors, non-steroidal anti-inflammatory agents,N-methyl d-aspartate receptor antagonists, opioid receptor agonists,phosphodiesterase inhibitors, prostaglandin analogs, prostaglandinreceptor agonists, renin inhibitors, selective serotonin reuptakeinhibitors, sodium channel blocker, soluble guanylate cyclasestimulators and activators, tricyclic antidepressants, vasopressinreceptor antagonists, and combinations thereof. Specific examples ofthese agents are detailed herein.

Accordingly, in yet another aspect of the invention, a pharmaceuticalcomposition comprises a compound of the invention, a second activeagent, and a pharmaceutically acceptable carrier. Third, fourth etc.active agents may also be included in the composition. In combinationtherapy, the amount of compound of the invention that is administered,as well as the amount of secondary agents, may be less than the amounttypically administered in monotherapy.

Compounds of the invention may be physically mixed with the secondactive agent to form a composition containing both agents; or each agentmay be present in separate and distinct compositions which areadministered to the patient simultaneously or at separate times. Forexample, a compound of the invention can be combined with a secondactive agent using conventional procedures and equipment to form acombination of active agents comprising a compound of the invention anda second active agent. Additionally, the active agents may be combinedwith a pharmaceutically acceptable carrier to form a pharmaceuticalcomposition comprising a compound of the invention, a second activeagent and a pharmaceutically acceptable carrier. In this embodiment, thecomponents of the composition are typically mixed or blended to create aphysical mixture. The physical mixture is then administered in atherapeutically effective amount using any of the routes describedherein.

Alternatively, the active agents may remain separate and distinct beforeadministration to the patient. In this embodiment, the agents are notphysically mixed together before administration but are administeredsimultaneously or at separate times as separate compositions. Suchcompositions can be packaged separately or may be packaged together in akit. When administered at separate times, the secondary agent willtypically be administered less than 24 hours after administration of thecompound of the invention, ranging anywhere from concurrent withadministration of the compound of the invention to about 24 hourspost-dose. This is also referred to as sequential administration. Thus,a compound of the invention can be orally administered simultaneously orsequentially with another active agent using two tablets, with onetablet for each active agent, where sequential may mean beingadministered immediately after administration of the compound of theinvention or at some predetermined time later (for example, one hourlater or three hours later). It is also contemplated that the secondaryagent may be administered more than 24 hours after administration of thecompound of the invention. Alternatively, the combination may beadministered by different routes of administration, that is, one orallyand the other by inhalation.

In one embodiment, the kit comprises a first dosage form comprising acompound of the invention and at least one additional dosage formcomprising one or more of the secondary agents set forth herein, inquantities sufficient to carry out the methods of the invention. Thefirst dosage form and the second (or third, etc.) dosage form togethercomprise a therapeutically effective amount of active agents for thetreatment or prevention of a disease or medical condition in a patient.

Secondary agent(s), when included, are present in a therapeuticallyeffective amount such that they are typically administered in an amountthat produces a therapeutically beneficial effect when co-administeredwith a compound of the invention. The secondary agent can be in the formof a pharmaceutically acceptable salt, solvate, optically purestereoisomer, and so forth. The secondary agent may also be in the formof a prodrug, for example, a compound having a carboxylic acid groupthat has been esterified. Thus, secondary agents listed herein areintended to include all such forms, and are commercially available orcan be prepared using conventional procedures and reagents.

In one embodiment, compounds of the invention are administered incombination with an adenosine receptor antagonist, representativeexamples of which include, but are not limited to, naxifylline,rolofylline, SLV-320, theophylline, and tonapofylline.

In one embodiment, compounds of the invention are administered incombination with an α-adrenergic receptor antagonist, representativeexamples of which include, but are not limited to, doxazosin, prazosin,tamsulosin, and terazosin.

Compounds of the invention may also be administered in combination witha β₁-adrenergic receptor antagonist (“β₁-blockers”). Representativeβ₁-blockers include, but are not limited to, acebutolol, alprenolol,amosulalol, arotinolol, atenolol, befunolol, betaxolol, bevantolol,bisoprolol, bopindolol, bucindolol, bucumolol, bufetolol, bufuralol,bunitrolol, bupranolol, bubridine, butofilolol, carazolol, carteolol,carvedilol, celiprolol, cetamolol, cloranolol, dilevalol, epanolol,esmolol, indenolol, labetolol, levobunolol, mepindolol, metipranolol,metoprolol such as metoprolol succinate and metoprolol tartrate,moprolol, nadolol, nadoxolol, nebivalol, nipradilol, oxprenolol,penbutolol, perbutolol, pindolol, practolol, pronethalol, propranolol,sotalol, sufinalol, talindol, tertatolol, tilisolol, timolol,toliprolol, xibenolol, and combinations thereof. In one particularembodiment, the β₁-antagonist is selected from atenolol, bisoprolol,metoprolol, propranolol, sotalol, and combinations thereof. Typically,the β₁-blocker will be administered in an amount sufficient to providefrom about 2-900 mg per dose.

In one embodiment, compounds of the invention are administered incombination with a β₂-adrenergic receptor agonist, representativeexamples of which include, but are not limited to, albuterol,bitolterol, fenoterol, formoterol, indacaterol, isoetharine,levalbuterol, metaproterenol, pirbuterol, salbutamol, salmefamol,salmeterol, terbutaline, vilanterol, and the like Typically, theβ₂-adrenergic receptor agonist will be administered in an amountsufficient to provide from about 0.05-500 μg per dose.

In one embodiment, compounds of the invention are administered incombination with an advanced glycation end product (AGE) breaker,examples of which include, by way of illustration and not limitation,alagebrium (or ALT-711), and TRC4149.

In another embodiment, compounds of the invention are administered incombination with an aldosterone antagonist, representative examples ofwhich include, but are not limited to, eplerenone, spironolactone, andcombinations thereof. Typically, the aldosterone antagonist will beadministered in an amount sufficient to provide from about 5-300 mg perday.

In one embodiment, compounds of the invention are administered incombination with an aminopeptidase N or dipeptidyl peptidase IIIinhibitor, examples of which include, by way of illustration and notlimitation, bestatin and PC18 (2-amino-4-methylsulfonyl butane thiol,methionine thiol).

Compounds of the invention can also be administered in combination withan angiotensin-converting enzyme (ACE) inhibitor. Representative ACEinhibitors include, but are not limited to, accupril, alacepril,benazepril, benazeprilat, captopril, ceranapril, cilazapril, delapril,enalapril, enalaprilat, fosinopril, fosinoprilat, imidapril, lisinopril,moexipril, monopril, moveltopril, pentopril, perindopril, quinapril,quinaprilat, ramipril, ramiprilat, saralasin acetate, spirapril,temocapril, trandolapril, zofenopril, and combinations thereof. In aparticular embodiment, the ACE inhibitor is selected from: benazepril,captopril, enalapril, lisinopril, ramipril, and combinations thereof.Typically, the ACE inhibitor will be administered in an amountsufficient to provide from about 1-150 mg per day.

In one embodiment, compounds of the invention are administered incombination with a dual-acting agent, such as an angiotensin-convertingenzyme/neprilysin (ACE/NEP) inhibitor, examples of which include, butare not limited to: AVE-0848((4S,7S,12bR)-7-[3-methyl-2(S)-sulfanylbutyramido]-6-oxo-1,2,3,4,6,7,8,12b-octahydropyrido[2,1-a][2]-benzazepine-4-carboxylicacid); AVE-7688 (ilepatril) and its parent compound; BMS-182657(2-[2-oxo-3(S)-[3-phenyl-2(S)-sulfanylpropionamido]-2,3,4,5-tetrahydro-1H-1-benzazepin-1-yl]aceticacid); CGS-26303([N-[2-(biphenyl-4-yl)-[(S)-(1H-tetrazol-5-yl)ethyl]amino]methylphosphonicacid); CGS-35601(N-[1-[4-methyl-2(S)-sulfanylpentanamido]cyclopentylcarbonyl]-L-tryptophan);fasidotril; fasidotrilate; enalaprilat; ER-32935 ((3R,6S,9aR)-6-[3(S)-methyl-2(S)-sulfanylpentanamido]-5-oxoperhydrothiazolo[3,2-a]azepine-3-carboxylicacid); gempatrilat; MDL-101264((4S,7S,12bR)-7-[2(S)-(2-morpholinoacetylthio)-3-phenylpropionamido]-6-oxo-1,2,3,4,6,7,8,12b-octahydropyrido[2,1-a][2]benzazepine-4-carboxylicacid); MDL-101287([4S-[4α,7α(R*),12bβ]]-7-[2-(carboxymethyl)-3-phenylpropionamido]-6-oxo-1,2,3,4,6,7,8,12b-octahydropyrido[2,1-a][2]benzazepine-4-carboxylicacid); omapatrilat; RB-105(N-[2(S)-(mercaptomethyl)-3(R)-phenylbutyl]-L-alanine); sampatrilat;SA-898((2R,4R)—N-[2-(2-hydroxyphenyl)-3-(3-mercaptopropionyl)thiazolidin-4-ylcarbonyl]-L-phenylalanine);Sch-50690(N-[1(5)-carboxy-2-[N2-(methanesulfonyl)-L-lysylamino]ethyl]-L-valyl-L-tyrosine);and combinations thereof, may also be included. In one particularembodiment, the ACE/NEP inhibitor is selected from: AVE-7688,enalaprilat, fasidotril, fasidotrilate, omapatrilat, sampatrilat, andcombinations thereof.

In one embodiment, compounds of the invention are administered incombination with an angiotensin-converting enzyme 2 (ACE2) activator orstimulator.

In one embodiment, compounds of the invention are administered incombination with an angiotensin-II vaccine, examples of which include,but are not limited to ATR12181 and CYT006-AngQb.

In one embodiment, compounds of the invention are administered incombination with an anticoagulant, representative examples of whichinclude, but are not limited to: coumarins such as warfarin; heparin;and direct thrombin inhibitors such as argatroban, bivalirudin,dabigatran, and lepirudin.

In yet another embodiment, compounds of the invention are administeredin combination with an anti-diabetic agent. Representative anti-diabeticagents include injectable drugs as well as orally effective drugs, andcombinations thereof. Examples of injectable drugs include, but are notlimited to, insulin and insulin derivatives. Examples of orallyeffective drugs include, but are not limited to: biguanides such asmetformin; glucagon antagonists; α-glucosidase inhibitors such asacarbose and miglitol; dipeptidyl peptidase IV inhibitors (DPP-IVinhibitors) such as alogliptin, denagliptin, linagliptin, saxagliptin,sitagliptin, and vildagliptin; meglitinides such as repaglinide;oxadiazolidinediones; sulfonylureas such as chlorpropamide, glimepiride,glipizide, glyburide, and tolazamide; thiazolidinediones such aspioglitazone and rosiglitazone; and combinations thereof.

In another embodiment, compounds of the invention are administered incombination with antidiarrheal treatments. Representative treatmentoptions include, but are not limited to, oral rehydration solutions(ORS), loperamide, diphenoxylate, and bismuth sabsalicylate.

In yet another embodiment, a compound of the invention is administeredin combination with an anti-glaucoma agent. Representative anti-glaucomaagents include, but are not limited to: a-adrenergic agonists such asbrimonidine; β₁-adrenergic receptor antagonists; topical β₁-blockerssuch as betaxolol, levobunolol, and timolol; carbonic anhydraseinhibitors such as acetazolamide, brinzolamide, or dorzolamide;cholinergic agonists such as cevimeline and DMXB-anabaseine; epinephrinecompounds; miotics such as pilocarpine; and prostaglandin analogs.

In yet another embodiment, compounds of the invention are administeredin combination with an anti-lipid agent. Representative anti-lipidagents include, but are not limited to: cholesteryl ester transferprotein inhibitors (CETPs) such as anacetrapib, dalcetrapib, andtorcetrapib; statins such as atorvastatin, fluvastatin, lovastatin,pravastatin, rosuvastatin and simvastatin; and combinations thereof.

In one embodiment, compounds of the invention are administered incombination with an anti-thrombotic agent. Representativeanti-thrombotic agents include, but are not limited to: aspirin;anti-platelet agents such as clopidogrel, prasugrel, and ticlopidine;heparin, and combinations thereof.

In one embodiment, compounds of the invention are administered incombination with an AT₁ receptor antagonist, also known as angiotensinII type 1 receptor blockers (ARBs). Representative ARBs include, but arenot limited to, abitesartan, azilsartan (e.g., azilsartan medoxomil),benzyllosartan, candesartan, candesartan cilexetil, elisartan,embusartan, enoltasosartan, eprosartan, EXP3174, fonsartan, forasartan,glycyllosartan, irbesartan, isoteoline, losartan, medoximil,milfasartan, olmesartan (e.g., olmesartan medoxomil), opomisartan,pratosartan, ripisartan, saprisartan, saralasin, sarmesin, TAK-591,tasosartan, telmisartan, valsartan, zolasartan, and combinationsthereof. In a particular embodiment, the ARB is selected from azilsartanmedoxomil, candesartan cilexetil, eprosartan, irbesartan, losartan,olmesartan medoxomil, irbesartan, saprisartan, tasosartan, telmisartan,valsartan, and combinations thereof. Exemplary salts and/or prodrugsinclude candesartan cilexetil, eprosartan mesylate, losartan potassiumsalt, and olmesartan medoxomil. Typically, the ARB will be administeredin an amount sufficient to provide from about 4-600 mg per dose, withexemplary daily dosages ranging from 20-320 mg per day.

Compounds of the invention may also be administered in combination witha dual-acting agent, such as an AT₁ receptor antagonist/neprilysininhibitor (ARB/NEP) inhibitor, examples of which include, but are notlimited to, compounds described in U.S. Publication Nos. 2008/0269305and 2009/0023228, both to Allegretti et al. filed on April 23, 2008,such as the compound,4′-{2-ethoxy-4-ethyl-5-[((S)-2-mercapto-4-methylpentanoylamino)-methyl]imidazol-1-ylmethyl}-3′-fluorobiphenyl-2-carboxylicacid.

Compounds of the invention may also be administered in combination withmultifunctional angiotensin receptor blockers as described in Kurtz &Klein (2009) Hypertension Research 32:826-834.

In one embodiment, compounds of the invention are administered incombination with a bradykinin receptor antagonist, for example,icatibant (HOE-140). It is expected that this combination therapy maypresent the advantage of preventing angioedema or other unwantedconsequences of elevated bradykinin levels.

In one embodiment, compounds of the invention are administered incombination with a calcium channel blocker. Representative calciumchannel blockers include, but are not limited to, amlodipine, anipamil,aranipine, barnidipine, bencyclane, benidipine, bepridil, clentiazem,cilnidipine, cinnarizine, diltiazem, efonidipine, elgodipine, etafenone,felodipine, fendiline, flunarizine, gallopamil, isradipine, lacidipine,lercanidipine, lidoflazine, lomerizine, manidipine, mibefradil,nicardipine, nifedipine, niguldipine, niludipine, nilvadipine,nimodipine, nisoldipine, nitrendipine, nivaldipine, perhexyline,prenylamine, ryosidine, semotiadil, terodiline, tiapamil, verapamil, andcombinations thereof. In a particular embodiment, the calcium channelblocker is selected from amlodipine, bepridil, diltiazem, felodipine,isradipine, lacidipine, nicardipine, nifedipine, niguldipine,niludipine, nimodipine, nisoldipine, ryosidine, verapamil, andcombinations thereof. Typically, the calcium channel blocker will beadministered in an amount sufficient to provide from about 2-500 mg perdose.

In one embodiment, compounds of the invention are administered incombination with a chymase inhibitor, such as TPC-806 and2-(5-formylamino-6-oxo-2-phenyl-1,6-dihydropyrimidine-1-yl)-N-[{3,4-dioxo-1-phenyl-7-(2-pyridyloxy)}-2-heptyl]acetamide (NK3201).

In one embodiment, compounds of the invention are administered incombination with a diuretic. Representative diuretics include, but arenot limited to: carbonic anhydrase inhibitors such as acetazolamide anddichlorphenamide; loop diuretics, which include sulfonamide derivativessuch as acetazolamide, ambuside, azosernide, bumetanide, butazolamide,chloraminophenamide, clofenamide, clopamide, clorexolone, disulfamide,ethoxolamide, furosemide, mefruside, methazolamide, piretanide,torsemide, tripamide, and xipamide, as well as non-sulfonamide diureticssuch as ethacrynic acid and other phenoxyacetic acid compounds such astienilic acid, indacrinone and quincarbate; osmotic diuretics such asmannitol; potassium-sparing diuretics, which include aldosteroneantagonists such as spironolactone, and Na⁺ channel inhibitors such asamiloride and triamterene; thiazide and thiazide-like diuretics such asalthiazide, bendroflumethiazide, benzylhydrochlorothiazide,benzthiazide, buthiazide, chlorthalidone, chlorothiazide,cyclopenthiazide, cyclothiazide, epithiazide, ethiazide, fenquizone,flumethiazide, hydrochlorothiazide, hydroflumethiazide, indapamide,methylclothiazide, meticrane, metolazone, paraflutizide, polythiazide,quinethazone, teclothiazide, and trichloromethiazide; and combinationsthereof. In a particular embodiment, the diuretic is selected fromamiloride, bumetanide, chlorothiazide, chlorthalidone, dichlorphenamide,ethacrynic acid, furosemide, hydrochlorothiazide, hydroflumethiazide,indapamide, methylclothiazide, metolazone, torsemide, triamterene, andcombinations thereof. The diuretic will be administered in an amountsufficient to provide from about 5-50 mg per day, more typically 6-25 mgper day, with common dosages being 6.25 mg, 12.5 mg or 25 mg per day.

Compounds of the invention may also be administered in combination withan endothelin converting enzyme (ECE) inhibitor, examples of whichinclude, but are not limited to, phosphoramidon, CGS 26303, andcombinations thereof.

In a particular embodiment, compounds of the invention are administeredin combination with an endothelin receptor antagonist. Representativeendothelin receptor antagonists include, but are not limited to:selective endothelin receptor antagonists that affect endothelin Areceptors, such as avosentan, ambrisentan, atrasentan, BQ-123,clazosentan, darusentan, sitaxentan, and zibotentan; and dual endothelinreceptor antagonists that affect both endothelin A and B receptors, suchas bosentan, macitentan, tezosentan).

In yet another embodiment, a compound of the invention is administeredin combination with one or more HMG-CoA reductase inhibitors, which arealso known as statins. Representative statins include, but are notlimited to, atorvastatin, fluvastatin, lovastatin, pitavastatin,pravastatin, rosuvastatin and simvastatin.

In one embodiment, compounds of the invention are administered incombination with a monoamine reuptake inhibitor, examples of whichinclude, by way of illustration and not limitation, norepinephrinereuptake inhibitors such as atomoxetine, buproprion and the buproprionmetabolite hydroxybuproprion, maprotiline, reboxetine, and viloxazine;selective serotonin reuptake inhibitors (SSRIs) such as citalopram andthe citalopram metabolite desmethylcitalopram, dapoxetine, escitalopram(e.g., escitalopram oxalate), fluoxetine and the fluoxetine desmethylmetabolite norfluoxetine, fluvoxamine (e.g., fluvoxamine maleate),paroxetine, sertraline and the sertraline metabolite demethylsertraline;dual serotonin-norepinephrine reuptake inhibitors (SNRIs) such asbicifadine, duloxetine, milnacipran, nefazodone, and venlafaxine; andcombinations thereof.

In another embodiment, compounds of the invention are administered incombination with a muscle relaxant, examples of which include, but arenot limited to: carisoprodol, chlorzoxazone, cyclobenzaprine,diflunisal, metaxalone, methocarbamol, and combinations thereof.

In one embodiment, compounds of the invention are administered incombination with a natriuretic peptide or analog, examples of whichinclude but are not limited to: carperitide, CD-NP (Nile Therapeutics),CU-NP, nesiritide, PL-3994 (Palatin Technologies, Inc.), ularitide,cenderitide, and compounds described in Ogawa et al (2004) J. Biol.Chem. 279:28625-31. These compounds are also referred to as natriureticpeptide receptor-A (NPR-A) agonists. In another embodiment, compounds ofthe invention are administered in combination with a natriuretic peptideclearance receptor (NPR-C) antagonist such as SC-46542, cANF (4-23), andAP-811 (Veale (2000) Bioorg Med Chem Lett 10:1949-52). For example,AP-811 has shown synergy when combined with the NEP inhibitor, thiorphan(Wegner (1995) Clin. Exper. Hypert. 17:861-876).

In another embodiment, compounds of the invention are administered incombination with a neprilysin (NEP) inhibitor. Representative NEPinhibitors include, but are not limited to: AHU-377; candoxatril;candoxatrilat; dexecadotril((+)-N-[2(R)-(acetylthiomethyl)-3-phenylpropionyl]glycine benzyl ester);CGS-24128(3-[3-(biphenyl-4-yl)-2-(phosphonomethylamino)propionamido]propionicacid); CGS-24592((S)-3-[3-(biphenyl-4-yl)-2-(phosphonomethylamino)propionamido]propionicacid); CGS-25155(N-[9(R)-(acetylthiomethyl)-10-oxo-1-azacyclodecan-2(S)-ylcarbonyl]-4(R)-hydroxy-L-prolinebenzyl ester); 3-(1-carbamoylcyclohexyl)propionic acid derivativesdescribed in WO 2006/027680 to Hepworth et al. (Pfizer Inc.); JMV-390-1(2(R)-benzyl-3-(N-hydroxycarbamoyl)propionyl-L-isoleucyl-L-leucine);ecadotril; phosphoramidon; retrothiorphan; RU-42827(2-(mercaptomethyl)-N-(4-pyridinyl)benzenepropionamide); RU-44004(N-(4-morpholinyl)-3-phenyl-2-(sulfanylmethyl)propionamide); SCH-32615((S)—N—[N-(1-carboxy-2-phenylethyl)-L-phenylalanyl]-β-alanine) and itsprodrug SCH-34826((S)—N—[N-[1-[[(2,2-dimethyl-1,3-dioxolan-4-yl)methoxy]carbonyl]-2-phenylethyl]-L-phenylalanyl]-(3-alanine);sialorphin; SCH-42495(N-[2(S)-(acetylsulfanylmethyl)-3-(2-methylphenyl)propionyl]-L-methionineethyl ester); spinorphin; SQ-28132(N-[2-(mercaptomethyl)-1-oxo-3-phenylpropyl]leucine); SQ-28603(N-[2-(mercaptomethyl)-1-oxo-3-phenylpropyl]-(3-alanine); SQ-29072(7-[[2-(mercaptomethyl)-1-oxo-3-phenylpropyl]amino]heptanoic acid);thiorphan and its prodrug racecadotril; UK-69578(cis-4-[[[1-[2-carboxy-3-(2-methoxyethoxy)propyl]cyclopentyl]carbonyl]amino]cyclohexanecarboxylicacid); UK-447,841(2-{1-[3-(4-chlorophenyl)propylcarbamoyl]-cyclopentylmethyl}-4-methoxybutyricacid); UK-505,749((R)-2-methyl-3-{1-[3-(2-methylbenzothiazol-6-yl)propylcarbamoyl]cyclopentyl}propionicacid); 5-biphenyl-4-yl-4-(3-carboxypropionylamino)-2-methylpentanoicacid and 5-biphenyl-4-yl-4-(3-carboxypropionylamino)-2-methylpentanoicacid ethyl ester (WO 2007/056546); daglutril[(3S,2′R)-3-{1-[2′-(ethoxycarbonyl)-4′-phenylbutyl]-cyclopentan-1-carbonylamino}-2,3,4,5-tetrahydro-2-oxo-1H-1-benzazepine-1-aceticacid] described in WO 2007/106708 to Khder et al. (Novartis AG); andcombinations thereof. In a particular embodiment, the NEP inhibitor isselected from AHU-377, candoxatril, candoxatrilat, CGS-24128,phosphoramidon, SCH-32615, SCH-34826, SQ-28603, thiorphan, andcombinations thereof. In a particular embodiment, the NEP inhibitor is acompound such as daglutril, which also has activity both as an inhibitorof the endothelin converting enzyme (ECE) and of NEP. Other dual actingECE/NEP compounds can also be used. The NEP inhibitor will beadministered in an amount sufficient to provide from about 20-800 mg perday, with typical daily dosages ranging from 50-700 mg per day, morecommonly 100-600 or 100-300 mg per day.

In one embodiment, compounds of the invention are administered incombination with a nitric oxide donor, examples of which include, butare not limited to nicorandil; organic nitrates such as pentaerythritoltetranitrate; and sydnonimines such as linsidomine and molsidomine.

In yet another embodiment, compounds of the invention are administeredin combination with a non-steroidal anti-inflammatory agent (NSAID).Representative NSAIDs include, but are not limited to: acemetacin,acetyl salicylic acid, alclofenac, alminoprofen, amfenac, amiprilose,amoxiprin, anirolac, apazone, azapropazone, benorilate, benoxaprofen,bezpiperylon, broperamole, bucloxic acid, carprofen, clidanac,diclofenac, diflunisal, diftalone, enolicam, etodolac, etoricoxib,fenbufen, fenclofenac, fenclozic acid, fenoprofen, fentiazac, feprazone,flufenamic acid, flufenisal, fluprofen, flurbiprofen, furofenac,ibufenac, ibuprofen, indomethacin, indoprofen, isoxepac, isoxicam,ketoprofen, ketorolac, lofemizole, lornoxicam, meclofenamate,meclofenamic acid, mefenamic acid, meloxicam, mesalamine, miroprofen,mofebutazone, nabumetone, naproxen, niflumic acid, oxaprozin, oxpinac,oxyphenbutazone, phenylbutazone, piroxicam, pirprofen, pranoprofen,salsalate, sudoxicam, sulfasalazine, sulindac, suprofen, tenoxicam,tiopinac, tiaprofenic acid, tioxaprofen, tolfenamic acid, tolmetin,triflumidate, zidometacin, zomepirac, and combinations thereof. In aparticular embodiment, the NSAID is selected from etodolac,flurbiprofen, ibuprofen, indomethacin, ketoprofen, ketorolac, meloxicam,naproxen, oxaprozin, piroxicam, and combinations thereof.

In one embodiment, compounds of the invention are administered incombination with an N-methyl d-aspartate (NMDA) receptor antagonist,examples of which include, by way of illustration and not limitation,including amantadine, dextromethorphan, dextropropoxyphene, ketamine,ketobemidone, memantine, methadone, and so forth.

In still another embodiment, compounds of the invention are administeredin combination with an opioid receptor agonist (also referred to asopioid analgesics). Representative opioid receptor agonists include, butare not limited to: buprenorphine, butorphanol, codeine, dihydrocodeine,fentanyl, hydrocodone, hydromorphone, levallorphan, levorphanol,meperidine, methadone, morphine, nalbuphine, nalmefene, nalorphine,naloxone, naltrexone, nalorphine, oxycodone, oxymorphone, pentazocine,propoxyphene, tramadol, and combinations thereof. In certainembodiments, the opioid receptor agonist is selected from codeine,dihydrocodeine, hydrocodone, hydromorphone, morphine, oxycodone,oxymorphone, tramadol, and combinations thereof.

In a particular embodiment, compounds of the invention are administeredin combination with a phosphodiesterase (PDE) inhibitor, particularly aPDE-V inhibitor. Representative PDE-V inhibitors include, but are notlimited to, avanafil, lodenafil, mirodenafil, sildenafil (Revatio®),tadalafil (Adcirca®), vardenafil (Levitra®), and udenafil.

In another embodiment, compounds of the invention are administered incombination with a prostaglandin analog (also referred to as prostanoidsor prostacyclin analogs). Representative prostaglandin analogs include,but are not limited to, beraprost sodium, bimatoprost, epoprostenol,iloprost, latanoprost, tafluprost, travoprost, and treprostinil, withbimatoprost, latanoprost, and tafluprost being of particular interest.

In yet another embodiment, compounds of the invention are administeredin combination with a prostaglandin receptor agonist, examples of whichinclude, but are not limited to, bimatoprost, latanoprost, travoprost,and so forth.

Compounds of the invention may also be administered in combination witha renin inhibitor, examples of which include, but are not limited to,aliskiren, enalkiren, remikiren, and combinations thereof.

In another embodiment, compounds of the invention are administered incombination with a selective serotonin reuptake inhibitor (SSRI).Representative SSRIs include, but are not limited to: citalopram and thecitalopram metabolite desmethylcitalopram, dapoxetine, escitalopram(e.g., escitalopram oxalate), fluoxetine and the fluoxetine desmethylmetabolite norfluoxetine, fluvoxamine (e.g., fluvoxamine maleate),paroxetine, sertraline and the sertraline metabolite demethylsertraline,and combinations thereof.

In one embodiment, compounds of the invention are administered incombination with a 5-HT_(1D) serotonin receptor agonist, examples ofwhich include, by way of illustration and not limitation, triptans suchas almotriptan, avitriptan, eletriptan, frovatriptan, naratriptanrizatriptan, sumatriptan, and zolmitriptan.

In one embodiment, compounds of the invention are administered incombination with a sodium channel blocker, examples of which include, byway of illustration and not limitation, carbamazepine, fosphenyloin,lamotrignine, lidocaine, mexiletine, oxcarbazepine, phenyloin, andcombinations thereof.

In one embodiment, compounds of the invention are administered incombination with a soluble guanylate cyclase stimulator or activator,examples of which include, but are not limited to ataciguat, riociguat,and combinations thereof.

In one embodiment, compounds of the invention are administered incombination with a tricyclic antidepressant (TCA), examples of whichinclude, by way of illustration and not limitation, amitriptyline,amitriptylinoxide, butriptyline, clomipramine, demexiptiline,desipramine, dibenzepin, dimetacrine, dosulepin, doxepin, imipramine,imipraminoxide, lofepramine, melitracen, metapramine, nitroxazepine,nortriptyline, noxiptiline, pipofezine, propizepine, protriptyline,quinupramine, and combinations thereof.

In one embodiment, compounds of the invention are administered incombination with a vasopressin receptor antagonist, examples of whichinclude, by way of illustration and not limitation, conivaptan andtolvaptan.

Combined secondary therapeutic agents may also be helpful in furthercombination therapy with compounds of the invention. For example,compounds of the invention can be combined with a diuretic and an ARB,or a calcium channel blocker and an ARB, or a diuretic and an ACEinhibitor, or a calcium channel blocker and a statin. Specific examplesinclude, a combination of the ACE inhibitor enalapril (in the maleatesalt form) and the diuretic hydrochlorothiazide, which is sold under themark Vaseretic®, or a combination of the calcium channel blockeramlodipine (in the besylate salt form) and the ARB olmesartan (in themedoxomil prodrug form), or a combination of a calcium channel blockerand a statin, all may also be used with the compounds of the invention.Other therapeutic agents such as α₂-adrenergic receptor agonists andvasopressin receptor antagonists may also be helpful in combinationtherapy. Exemplary α₂-adrenergic receptor agonists include clonidine,dexmedetomidine, and guanfacine.

The following formulations illustrate representative pharmaceuticalcompositions of the invention.

Exemplary Hard Gelatin Capsules For Oral Administration

A compound of the invention (50 g), 440 g spray-dried lactose and 10 gmagnesium stearate are thoroughly blended. The resulting composition isthen loaded into hard gelatin capsules (500 mg of composition percapsule). Alternately, a compound of the invention (20 mg) is thoroughlyblended with starch (89 mg), microcrystalline cellulose (89 mg) andmagnesium stearate (2 mg). The mixture is then passed through a No. 45mesh U.S. sieve and loaded into a hard gelatin capsule (200 mg ofcomposition per capsule).

Alternately, a compound of the invention (30 g), a secondary agent (20g), 440 g spray-dried lactose and 10 g magnesium stearate are thoroughlyblended, and processed as described above.

Exemplary Gelatin Capsule Formulation For Oral Administration

A compound of the invention (100 mg) is thoroughly blended withpolyoxyethylene sorbitan monooleate (50 mg) and starch powder (250 mg).The mixture is then loaded into a gelatin capsule (400 mg of compositionper capsule). Alternately, a compound of the invention (70 mg) and asecondary agent (30 mg) are thoroughly blended with polyoxyethylenesorbitan monooleate (50 mg) and starch powder (250 mg), and theresulting mixture loaded into a gelatin capsule (400 mg of compositionper capsule).

Alternately, a compound of the invention (40 mg) is thoroughly blendedwith microcrystalline cellulose (Avicel PH 103; 259.2 mg) and magnesiumstearate (0.8 mg). The mixture is then loaded into a gelatin capsule(Size #1, White, Opaque) (300 mg of composition per capsule).

Exemplary Tablet Formulation For Oral Administration

A compound of the invention (10 mg), starch (45 mg) and microcrystallinecellulose (35 mg) are passed through a No. 20 mesh U.S. sieve and mixedthoroughly. The granules so produced are dried at 50-60° C. and passedthrough a No. 16 mesh U.S. sieve. A solution of polyvinylpyrrolidone (4mg as a 10% solution in sterile water) is mixed with sodiumcarboxymethyl starch (4.5 mg), magnesium stearate (0.5 mg), and talc (1mg), and this mixture is then passed through a No. 16 mesh U.S. sieve.The sodium carboxymethyl starch, magnesium stearate and talc are thenadded to the granules. After mixing, the mixture is compressed on atablet machine to afford a tablet weighing 100 mg.

Alternately, a compound of the invention (250 mg) is thoroughly blendedwith microcrystalline cellulose (400 mg), silicon dioxide fumed (10 mg),and stearic acid (5 mg). The mixture is then compressed to form tablets(665 mg of composition per tablet).

Alternately, a compound of the invention (400 mg) is thoroughly blendedwith cornstarch (50 mg), croscarmellose sodium (25 mg), lactose (120mg), and magnesium stearate (5 mg). The mixture is then compressed toform a single-scored tablet (600 mg of composition per tablet).

Alternately, a compound of the invention (100 mg) is thoroughly blendedwith cornstarch (100 mg) with an aqueous solution of gelatin (20 mg).The mixture is dried and ground to a fine powder. Microcrystallinecellulose (50 mg) and magnesium stearate (5 mg) are then admixed withthe gelatin formulation, granulated and the resulting mixture compressedto form tablets (100 mg of the compound of the invention per tablet).

Exemplary Suspension Formulation For Oral Administration

The following ingredients are mixed to form a suspension containing 100mg of the compound of the invention per 10 mL of suspension:

Ingredients Amount Compound of the invention 1.0 g Fumaric acid 0.5 gSodium chloride 2.0 g Methyl paraben 0.15 g Propyl paraben 0.05 gGranulated sugar 25.5 g Sorbitol (70% solution) 12.85 g Veegum ® K(magnesium aluminum silicate) 1.0 g Flavoring 0.035 mL Colorings 0.5 mgDistilled water q.s. to 100 mL

Exemplary Liquid Formulation For Oral Administration

A suitable liquid formulation is one with a carboxylic acid-based buffersuch as citrate, lactate and maleate buffer solutions. For example, acompound of the invention (which may be pre-mixed with DMSO) is blendedwith a 100 mM ammonium citrate buffer and the pH adjusted to pH 5, or isblended with a 100 mM citric acid solution and the pH adjusted to pH 2.Such solutions may also include a solubilizing excipient such as acyclodextrin, for example the solution may include 10 wt %hydroxypropyl-P-cyclodextrin.

Other suitable formulations include a 5% NaHCO₃ solution, with orwithout cyclodextrin.

Exemplary Injectable Formulation For Administration By Injection

A compound of the invention (0.2 g) is blended with 0.4 M sodium acetatebuffer solution (2.0 mL). The pH of the resulting solution is adjustedto pH 4 using 0.5 N aqueous hydrochloric acid or 0.5 N aqueous sodiumhydroxide, as necessary, and then sufficient water for injection isadded to provide a total volume of 20 mL. The mixture is then filteredthrough a sterile filter (0.22 micron) to provide a sterile solutionsuitable for administration by injection.

Exemplary Compositions For Administration By Inhalation

A compound of the invention (0.2 mg) is micronized and then blended withlactose (25 mg). This blended mixture is then loaded into a gelatininhalation cartridge. The contents of the cartridge are administeredusing a dry powder inhaler, for example.

Alternately, a micronized compound of the invention (10 g) is dispersedin a solution prepared by dissolving lecithin (0.2 g) in demineralizedwater (200 mL). The resulting suspension is spray dried and thenmicronized to form a micronized composition comprising particles havinga mean diameter less than about 1.5 um. The micronized composition isthen loaded into metered-dose inhaler cartridges containing pressurized1,1,1,2-tetrafluoroethane in an amount sufficient to provide about 10 μgto about 500 μg of the compound of the invention per dose whenadministered by the inhaler.

Alternately, a compound of the invention (25 mg) is dissolved in citratebuffered (pH 5) isotonic saline (125 mL). The mixture is stirred andsonicated until the compound is dissolved. The pH of the solution ischecked and adjusted, if necessary, to pH 5 by slowly adding aqueous 1 NNaOH. The solution is administered using a nebulizer device thatprovides about 10 μg to about 500 μg of the compound of the inventionper dose.

EXAMPLES

The following Preparations and Examples are provided to illustratespecific embodiments of the invention. These specific embodiments,however, are not intended to limit the scope of the invention in any wayunless specifically indicated.

The following abbreviations have the following meanings unless otherwiseindicated and any other abbreviations used herein and not defined havetheir standard, generally accepted meaning:

-   -   AcOH acetic acid    -   DCM dichloromethane or methylene chloride    -   DIPEA N,N-diisopropylethylamine    -   DMAP 4-dimethylaminopyridine    -   DMF N,N-dimethylformamide    -   EDC 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide    -   Et₃N triethylamine    -   Et₂O diethyl ether    -   EtOAc ethyl acetate    -   EtOH ethanol    -   HATU N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uronium        hexafluorophosphate    -   HEPES 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid    -   HOBt 1-hydroxybenzotriazole    -   MeCN acetonitrile    -   MeOH methanol    -   MeTHF 2-methyltetrahydrofuran    -   SilicaCat®DPP-Pd silica based diphenylphosphine palladium (II)        catalyst    -   SilicaCat®Pd(0) silica based palladium (0) catalyst    -   THF tetrahydrofuran

Unless noted otherwise, all materials, such as reagents, startingmaterials and solvents, were purchased from commercial suppliers (suchas Sigma-Aldrich, Fluka Riedel-de Haën, and the like) and were usedwithout further purification.

Reactions were run under nitrogen atmosphere, unless noted otherwise.The progress of reactions were monitored by thin layer chromatography(TLC), analytical high performance liquid chromatography (anal. HPLC),and mass spectrometry, the details of which are given in specificexamples. Solvents used in analytical HPLC were as follows: solvent Awas 98% H₂O/2% MeCN/1.0 mL/L TFA; solvent B was 90% MeCN/10% H₂O/1.0mL/L TFA.

Reactions were worked up as described specifically in each preparationfor example; commonly reaction mixtures were purified by extraction andother purification methods such as temperature-, and solvent-dependentcrystallization, and precipitation. In addition, reaction mixtures wereroutinely purified by preparative HPLC, typically using Microsorb C18and Microsorb BDS column packings and conventional eluents. Progress ofreactions was typically measured by liquid chromatography massspectrometry (LCMS). Characterization of isomers were done by NuclearOverhauser effect spectroscopy (NOE). Characterization of reactionproducts was routinely carried out by mass and ¹H-NMR spectrometry. ForNMR measurement, samples were dissolved in deuterated solvent (CD₃OD,CDCl₃, or DMSO-d₆), and ¹H-NMR spectra were acquired with a VarianGemini 2000 instrument (400 MHz) under standard observation conditions.Mass spectrometric identification of compounds was typically conductedusing an electrospray ionization method (ESMS) with an AppliedBiosystems (Foster City, Calif.) model API 150 EX instrument or anAgilent (Palo Alto, Calif.) model 1200 LC/MSD instrument.

Preparation 1(R)-3-(N-biphenyl-4-ylmethyl-N′-t-butoxycarbonylhydrazino)-2-hydroxypropionicAcid Methyl Ester (2A) and(S)-3-(N-biphenyl-4-ylmethyl-N′-t-butoxycarbonylhydrazino)-2-hydroxypropionicAcid Methyl Ester (2B)

4-(Bromomethyl)biphenyl (2.0 g, 8.1 mmol, 1.0 eq.) and DIPEA (1.4 mL,1.0 eq.) were dissolved in DMF (40.0 mL). t-Butyl carbazate (2.1 g, 16.2mmol, 2.0 eq.) was added and the mixture was stirred at room temperatureovernight. The mixture was partially concentrated, and the residue waspartitioned between EtOAc and a saturated aqueous NaHCO₃ solution. TheEtOAc layer was then dried over Na₂SO₄ and concentrated. The crudeproduct was purified by flash chromatography (0-60% EtOAc/hexanes with0.5% DIPEA) to yield compound 1,N′-biphenyl-4-ylmethyl-hydrazinecarboxylic acid t-butyl ester (1.7 g).

Compound 1 (830 mg, 2.8 mmol, 1.0 eq.) was dissolved in isopropylalcohol (20.0 mL). Methyl (2R)-glycidate (365 μL, 4.2 mmol, 1.5 eq.) wasadded and the mixture was heated at 85° C. The mixture was allowed tostir overnight and was then partitioned between EtOAc and a saturatedaqueous NaHCO₃ solution. The EtOAc layer was dried over Na₂SO₄ andconcentrated to yield compound 2A (803 mg), which was used withoutfurther purification. The procedure was repeated using methyl(2S)-glycidate (365 μL, 4.2 mmol, 1.5 eq.) to give compound 2B (717 mg),which was used without further purification.

Preparation 2 (R)-3-(N-Biphenyl-4-ylmethyl-hydrazino)-2-hydroxypropionicAcid Methyl Ester

(R)-3-(N-biphenyl-4-ylmethyl-N′-t-butoxycarbonylhydrazino)-2-hydroxypropionicacid methyl ester (300 mg, 749 μmol, 1.0 eq.) was dissolved in DCM (3.0mL). TFA (3.0 mL) was added and the mixture was stirred at roomtemperature until the reaction was complete (approximately 1 hour). Themixture was concentrated to yield the title compound, which was usedwithout further purification.

Example 15-[N-Biphenyl-4-ylmethyl-N′—((R)-2-carboxy-2-hydroxyethyl)hydrazinocarbonyl]-1H-pyrazole-3-carboxylicAcid

1H-pyrazole-3,5-dicarboxylic acid (58.4 mg, 374 μmol, 1.2 eq.) wasdissolved in DMF (2 mL). DIPEA (163 μL, 3.0 eq.) was added followed byHATU (142 mg, 374 μmol, 1.2 eq.) and the resulting solution was stirredfor 30 minutes.(R)-3-(N-Biphenyl-4-ylmethyl-hydrazino)-2-hydroxy-propionic acid methylester (93.7 mg, 312 μmol, 1.0 eq.) in DMF (2 mL) was then added and themixture was stirred at room temperature overnight. The mixture wasconcentrated and the crude intermediate was used in the next stepwithout further purification.

The crude intermediate was dissolved in THF (2.0 mL) and lithiumhydroxide monohydrate (131 mg, 3.1 mmol) in water (2.0 mL) was added.The mixture was stirred at room temperature for approximately 2.5 hours.The reaction was quenched by the addition of AcOH (10 eq.) and themixture was concentrated. The crude product was purified by preparativeHPLC (10-70% MeCN/H₂O) to yield the title compound as a TFA salt (31.2mg; purity 100%). MS m/z [M+H]⁺ calc'd for C₂₁H₂₀N₄O₆, 425.14; found425.2.

Example 2

Following the procedures described in the examples herein, andsubstituting the appropriate starting materials and reagents, compoundshaving the following formula were prepared as TFA salts:

 

MS m/z: [M + H⁺ Ex. R¹ R³ R⁴ Formula calcd found 1 —OH —COOH HC₂₁H₂₀N₄O₆ 425.14 425.2 2 —OH —C(O)NH(CH₂)₂—OH H C₂₃H₂₅N₅O₆ 468.18 468.43 —OH —C(O)NH(CH₂)₂—SO₂NH₂ H C₂₃H₂₆N₆O₇S 531.16 531.4 4 —OH—C(O)NH-cyclopropyl H C₂₄H₂₅N₅O₅ 464.19 464.4 5 —OH—C(O)N(CH₃)—(CH₂)₂—OCH₃ H C₂₅H₂₉N₅O₆ 496.21 496.6 6 —OH —C(O)N(CH₃)₂ HC₂₃H₂₅N₅O₅ 452.19 452.4 7 —OH —C(O)N(CH₃)CH₂—CH(CH₃)₂ H C₂₆H₃₁N₅O₅494.23 494.6 8 —OH

H C₂₄H₂₅N₅O₅ 464.19 464.4 9 —OH

H C₂₅H₂₇N₅O₅ 478.20 478.4 10 —OH

H C₂₅H₂₇N₅O₆ 494.20 494.4 11 —OH

H C₂₅H₂₇N₅O₆ 494.20 494.4 12 —OH

H C₂₅H₂₇N₅O₆ 494.20 494.4 13 —OH

H C₂₅H₂₅N₅O₅ 476.19 476.4 14 —OH

H C₂₆H₂₉N₅O₅ 492.22 492.4 15 —OH

H C₂₅H₂₇N₅O₆ 494.20 494.4 16 —OH phenyl H C₂₆H₂₄N₄O₄ 457.18 457.4

-   1.    5-[N′-Biphenyl-4-ylmethyl-N′—((S)-2-carboxy-2-hydroxyethyl)-hydrazinocarbonyl]-1H-pyrazole-3-carboxylic    acid-   2.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(2-hydroxyethylcarbamoyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   3.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(2-sulfamoylethylcarbamoyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   4.    (R)-3-[N-Biphenyl-4-ylmethyl-N′-(5-cyclopropylcarbamoyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxypropionic    acid-   5.    (R)-3-(N-Biphenyl-4-ylmethyl-N′-{5-[(2-methoxyethyl)methylcarbamoyl]-2H-pyrazole-3-carbonyl}hydrazino)-2-hydroxypropionic    acid-   6.    (R)-3-[N-Biphenyl-4-ylmethyl-N′-(5-dimethylcarbamoyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxypropionic    acid-   7.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(isobutylmethylcarbamoyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   8.    (R)-3-{N′-[5-(Azetidine-1-carbonyl)-2H-pyrazole-3-carbonyl]-N-biphenyl-4-ylmethylhydrazino}-2-hydroxypropionic    acid-   9.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(pyrrolidine-1-carbonyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   10.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(3-hydroxy-pyrrolidine-1-carbonyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   11.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-((R)-3-hydroxy-pyrrolidine-1-carbonyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   12.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-((S)-3-hydroxy-pyrrolidine-1-carbonyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   13.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(2,5-dihydro-pyrrole-1-carbonyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   14.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(piperidine-1-carbonyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   15.    (R)-3-{N-Biphenyl-4-ylmethyl-N′-[5-(morpholine-4-carbonyl)-2H-pyrazole-3-carbonyl]hydrazino}-2-hydroxypropionic    acid-   16.    (R)-3-[N-Biphenyl-4-ylmethyl-N′-(5-phenyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxypropionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 17 —OH —COOH 2,6-diF,C₂₈H₂₃ClF₂N₄O₆ 585.13 585.2 4-Cl- benzyl 18 —OH —COOH 2,3,5,6-C₂₉H₂₄F₄N₄O₇ 617.16 617.4 tetraF, 4- methoxy benzyl

-   17.    5-[N′-Biphenyl-4-ylmethyl-N′—((R)-2-carboxy-2-hydroxyethyl)-hydrazinocarbonyl]-2-(4-chloro-2,6-difluorobenzyl)-2H-pyrazole-3-carboxylic    acid-   18.    5-[N′-Biphenyl-4-ylmethyl-N′—((R)-2-carboxy-2-hydroxyethyl)-hydrazinocarbonyl]-2-(2,3,5,6-tetrafluoro-4-methoxybenzyl)-2H-pyrazole-3-carboxylic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 19 —OH —OH HC₂₀H₁₉N₃O₆ 398.13 398.4

-   19.    (R)-3-[N-Biphenyl-4-ylmethyl-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 20 —OH H H C₁₉H₁₉N₅O₄382.14 382.4

-   20.    (S)-3-[N-Biphenyl-4-ylmethyl-N′-(4H-[1,2,4]triazole-3-carbonyl)hydrazino]-2-hydroxypropionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 21 —OH H H C₁₉H₁₉N₅O₄382.14 382.2

-   21.    (R)-3-[N-Biphenyl-4-ylmethyl-N′-(3H-[1,2,3]triazole-4-carbonyl)hydrazino]-2-hydroxypropionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 22 —OH H H C₂₂H₂₀N₆O₄433.15 433.2

-   22.    (S)-3-[N-Biphenyl-4-ylmethyl-N′-(3H-[1,2,3]triazolo[4,5-b]pyridine-6-carbonyl)hydrazino]-2-hydroxypropionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 23 —OH F H C₂₃H₂₀FN₅O₄450.15 450.0 24 —OH F H C₂₃H₂₀FN₅O₄ 450.15 450.0 25 —OH Cl HC₂₃H₂₀ClN₅O₄ 466.12 466.0

-   23.    (R)-3-[N-Biphenyl-4-ylmethyl-N′-(7-fluoro-1H-benzotriazole-5-carbonyl)-hydrazino]-2-hydroxypropionic    acid-   24.    (S)-3-[N-Biphenyl-4-ylmethyl-N′-(7-fluoro-1H-benzotriazole-5-carbonyl)-hydrazino]-2-hydroxypropionic    acid-   25.    (S)-3-[N-Biphenyl-4-ylmethyl-N′-(7-chloro-1H-benzotriazole-5-carbonyl)-hydrazino]-2-hydroxypropionic    acid

Preparation 3 (R)-3-[N-(4-bromobenzyl)-N′-t-butoxycarbonyl-hydrazino]-2-hydroxy-propionic Acid Methyl Ester (compound 2)and (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)hydrazino]-2-hydroxypropionicAcid Ethyl Ester (compound 3)

4-Bromobenzyl bromide (5.0 g, 20 mmol) and DIPEA (3.48 mL, 20.0 mmol)were dissolved in DMF (20 mL). t-Butyl carbazate (7.9 g, 60.0 mmol) wasadded and the mixture was stirred at room temperature until the reactionwas complete. The mixture was partially concentrated, then the residuewas partitioned between EtOAc and a saturated aqueous NaHCO₃ solution.The EtOAc layer was then dried over Na₂SO₄ and concentrated. The crudeproduct was purified by flash chromatography to yield compound 1(3.8 g)

Compound 1 (1.9 g, 6.3 mmol) was dissolved in isopropyl alcohol (26.4mL). Methyl (2R)-glycidate (1.1 mL, 12.6 mmol) was added and the mixturewas heated at 90° C. until the reaction was complete (˜4 days). Themixture was cooled to room temperature and concentrated to yieldcompound 2 (2.5 g) as a white solid.

Compound 2 (600 mg, 1 mmol), 3-chlorophenylboronic acid (419 mg, 2.7mmol), and K₂CO₃ (617 mg, 4.5 mmol) were combined in EtOH (5 mL) andwater (1 mL), followed by the addition of SilicaCat®Pd(0) (0.09 mmol/gloading, 1160 mg, 104 μmol). The mixture was heated at 120° C. until thereaction was complete (˜30 minutes). The mixture was filtered andconcentrated. The residue was dissolved into MeN/AcOH and purified byreverse phase chromatography (55 g column; gradient 30-95% MeCN in waterwith 0.1% TFA). The clean fractions were collected, concentrated andthen dissolved in 4M HCl in dioxane (6 mL) and EtOH (6 mL). The mixturewas stirred at room temperature overnight, then concentrated to compound3 (250 mg), which was used without further purification.

Preparation 4(R)-3-[N′-t-Butoxycarbonyl-N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionicAcid

(R)-3-[N-(4-Bromobenzyl)-N′-t-butoxycarbonyl-hydrazino]-2-hydroxy-propionicacid methyl ester (1.0 g, 2.5 mmol), 3-chlorophenylboronic acid (776 mg,5.0 mmol), and K₂CO₃ (857 mg, 6.2 mmol) were dissolved in a mixture ofTHF (18 mL) and water (18 mL). The reaction flask was then purged withnitrogen and tetrakis(triphenylphosphine) palladium(0) (286 mg, 248μmol) was added. The mixture was stirred at 90° C. overnight (˜18hours). The mixture was diluted with saturated aqueous ammonium chlorideand extracted with EtOAc. The organic layer was collected, dried andconcentrated. The product was purified (Interchim reverse phasechromatography column, 10-80% MeCN in water) to yield the titlecompound.

Preparation 5(S)-3-[N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionicAcid Isopropyl Ester

4-Formylphenylboronic acid (18 g, 120 mmol) was combined with MeTHF (300mL), 3-chlorobromobenzene (14.1 mL, 120 mmol) and 1 M of aqueous Na₂CO₃(120 mL). The mixture was flushed with nitrogen three times and1,1′-bis(di-t-butylphosphino) ferrocene palladium dichloride (540 mg,840 μmol) was added. The mixture was again flushed with nitrogen threetimes, then stirred for 30 minutes while increasing the temperature to30° C. The mixture was then heated to 50° C. until the reaction wascomplete (˜2 hours). The mixture was cooled to room temperature, 1 Maqueous Na₂CO₃ (120 mL) was added, and the mixture was stirred overnightat room temperature. The layers were separated and the organic layer(dark brown color) was collected and dried over NaSO₄ and filtered. Itwas partially concentrated (to a 150 mL volume. To the solution wasadded Si—SH (mercaptan modified silica gel, ˜2 g). The mixture wasstirred at room temperature for 2 hours the filtered through Celite®.The cake was washed with MeTHF (100 mL) to yield compound 1 (25 g),which was used without further purification.

Compound 1 (25.0 g, 115.4 mmol) was combined with MeTHF (150 mL) andt-butyl carbazate (15.6 g, 118.0 mmol), and stirred at room temperaturefor one hour. AcOH (5 mL) was added and the resulting mixture wasstirred for one hour, yield compound 2, which was allowed to sitovernight.

A mixture of Compound 2 in MeTHF (250 mL) and AcOH (20.0 mL) was flushedwith nitrogen and cooled with an ice bath to 0° C. After stirring for 30minutes, sodium cyanoborohydride (8.7 g, 138 mmol) was added over 5minutes. The resulting mixture was stirred at 0° C. for one hour, slowlywarmed to room temperature and stirred until completion (˜20 hours). Themixture was cooled with an ice bath and 1 M aqueous NaOH (346.2 mL,346.2 mmol) was added. MeTHF (100 mL, 1.0 mol) was then added and themixture was allowed to warm to room temperature. The layers wereseparated and the organic layer was washed with 1 M aqueous NaOH (150mL, 150 mmol). The layers were separated and the organic layer was driedover Na₂SO₄, filtered, and concentrated to yield an oil, which wasdissolved in ether (250 mL, 2.4 mol) and stirred overnight. The mixturewas concentrated to yield compound 3 (35 g), which was used withoutfurther purification.

Compound 3 (20.0 g, 60.1 mmol) and methyl (2S)-glycidate (5.8 mL, 66.1mmol) were combined in isopropyl alcohol (170 mL) and the mixture washeated at 90° C. and monitored until the reaction was complete (severaldays), adding additional aliquots of methyl (2S)-glycidate (1.8 mL and 2mL) as the reaction progressed. The mixture was cooled to roomtemperature and allowed to sit overnight. The solids were filtered off,rinsed with isopropyl alcohol and dried (16 g total; 20% compound 4 and80% compound 5).

Isopropyl alcohol (200 mL, 2 mol) was cooled in an ice bath for 15minutes. Acetyl chloride (10 mL, 200 mmol) was added, followed byCompound 5 (12.6 g, 27.2 mmol). The resulting mixture was stirred atroom temperature for ˜48 hours. The precipitate from crude reactionmixture was filtered, dried under vacuum, then rinsed with MeCN (40 mL)and dried under vacuum to yield the title compound (6.8 g; 98% purity).

Example 3 A.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Ethyl Ester B.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid

-   3-Hydroxyisoxazole-5-carboxylic acid (888 mg, 6.9 mmol), HATU (2.6    g, 6.9 mmol) and DMF were combined and the resulting mixture was    stirred for 5 minutes at room temperature. DIPEA (2.3 mL, 13.2 mmol)    and    (R)-3′-[N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester (2.0 g, 5.7 mmol) were added and the resulting    mixture was stirred until the reaction was complete (20 minutes).    The reaction was quenched with water, the mixture was diluted with    EtOAc, then washed with water and saturated aqueous NaCl. The    organic layer was dried, concentrated, and purified by flash    chromatography (50-90% EtOAc in hexanes with 0.1% Et₃N). The clean    fractions were collected and concentrated. The organic layer, was    dissolved into DCM, and the precipitate was filtered and rinsed with    DCM to yield the ester compound A as a TFA salt (1.3 g; purity 96%).    MS m/z [M+H]⁺ calc'd for C₂₂H₂₂ClN₃O₆, 460.12; found 460.4.

A portion of the ester compound A (350 mg) was dissolved in 1M LiOH (4mL) and EtOH (10 mL). The resulting mixture was stirred at roomtemperature until the reaction was complete (1 hour). The mixture wasconcentrated, dissolved in AcOH and purified (C18 reverse phase column)The clean fractions were collected and lyophilized to yield the acidcompound B as a TFA salt (280 mg; purity 99%). MS m/z [M+H]⁺ calc'd forC₂₀H₁₈ClN₃O₆, 432.09; found 432.4.

C.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isopropyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid ethyl ester (1.4 g, 3.0 mmol) was dissolved in isopropyl alcohol(20 mL, 0.2 mol) and 4 M HCl in dioxane (9 mL, 40 mmol) was added. Themixture was stirred at room temperature overnight (18 hours). Themixture was warmed to 60° C. for 1 hour, then cooled back to roomtemperature and stirred for 2 hours. The mixture was concentrated andpurified (Interchim C18 reverse phase chromatography column, 30-90% MeCNin water for 22 minutes). The clean fractions were combined andlyophilized to yield the title compound (110 mg; purity 98%). MS m/z[M+H]⁺ calc'd for C₂₃H₂₄ClN₃O₆, 474.14; found 474.2.

D.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Butyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid (60 mg, 0.1 mmol) was dissolved in 1-propanol (4 mL, 50 mmol) and 4M HCl in dioxane (700 mL, 3 mmol) was added. The mixture was stirred atroom temperature until the reaction was complete (˜3 hours), thenevaporated under reduced pressure and purified (Interchim reverse phasechromatography column, 30-95% MeCN in water with 5% TFA). The cleanfractions were combined and lyophilized, then purified by preparativeHPLC to yield the title compound (43 mg, purity 95%). MS m/z [M+H]⁺calc'd for C₂₄H₂₆ClN₃O₆, 488.15; found 488.4.

E.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isobutyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid ethyl ester (1.5 g, 3.3 mmol) was dissolved in isobutyl alcohol (20mL, 200 mmol) and 4 M HCl in dioxane (10 mL, 40 mmol) was added. Themixture was stirred at room temperature for 6 hours. The mixture wasconcentrated, dissolved in water/MeCNe/MeOH, and purified (Interchim C18reverse phase chromatography column, 25-75% MeCN in water for 22minutes). The clean fractions were combined and lyophilized to yield thetitle compound (948 mg; purity 99%). MS m/z [M+H]⁺ calc'd forC₂₄H₂₆ClN₃O₆, 488.15; found 488.4.

F.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Benzyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid ethyl ester (1.5 g, 3.3 mmol) was dissolved in benzyl alcohol (20mL, 100 mmol) and 4 M HCl in dioxane (10 mL, 40 mmol) was added. Themixture was stirred at room temperature for 6 hours. The mixture wasevaporated under reduced pressure and purified (Interchim C18 reversephase chromatography column, 30-95% MeCN in water with 0.05% TFA). Theclean fractions were combined, lyophilized and purified to yield thetitle compound (688 mg; purity 98%). MS m/z [M+H]⁺ calc'd forC₂₇H₂₄ClN₃O₆, 522.14; found 522.2.

G.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicacid 5-methyl-2-oxo-[1,3]-dioxol-4-ylmethyl Ester

(R)-3-[N′-t-Butoxycarbonyl-N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionicacid (150 mg, 356 μmol), HOBt (140 mg, 1.1 mmol), EDC (0.19 mL, 1.1mmol) were dissolved into DCM. The mixture was stirred for 10 minutes,then 4-hydroxymethyl-5-methyl-[1,3]dioxol-2-one (370 mg, 2.8 mmol) and4-methylmorpholine (160 μL, 1.4 mmol) were added. The mixture wasstirred at room temperature for 2 hours. The mixture was concentratedand purified (combiflash. 10-95% EtOAc in hexanes with 0.01% Et₃N). Theclean fractions were combined and concentrated. MeCN (10 mL, 200 mmol)and 4 M HCl in dioxane (3 mL, 10 mmol) was added and the mixture wasstirred at room temperature for 3 hours. The solvent was removed toyield an intermediate HCl salt. 3-hydroxyisoxazole-5-carboxylic acid (55mg, 430 μmol) and HATU (160 mg, 430 μmol) were combined in DMF (5 mL, 60mmol). The resulting mixture was stirred for 5 minutes followed by theaddition of DIPEA (120 μL, 710 μmol) and the intermediate HCl salt. Themixture was stirred for 30 minutes then evaporated under reducedpressure and purified by preparative HPLC to yield the title compound asa TFA salt (37 mg; purity 95%). MS m/z [M+H]⁺ calc'd for C₂₅H₂₂ClN₃O₉,544.10; found 544.4.

H.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Hexyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid ethyl ester (50 mg, 0.1 mmol) was dissolved in 1-hexanol (4 mL, 30mmol) and 4 M HCl in dioxane (500 μL, 2 mmol) was added. The mixture wasstirred at room temperature overnight. The mixture was evaporated underreduced pressure and purified by preparative HPLC to yield the titlecompound as a TFA salt (21 mg; purity 95%). MS m/z [M+H]⁺ calc'd forC₂₆H₃₀ClN₃O₆, 516.18; found 516.6.

I.(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Heptyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid ethyl ester (50 mg, 0.1 mmol) was dissolved in 1-heptanol (4 mL, 30mmol) and 4 M HCl in dioxane (500 μL, 2 mmol) was added. The mixture wasstirred at room temperature overnight. The mixture was evaporated underreduced pressure and purified by preparative HPLC to yield the titlecompound as a TFA salt (39 mg; purity 95%). MS m/z [M+H]⁺ calc'd forC₂₇H₃₂ClN₃O₆, 530.20; found 530.2.

J.(S)-3-[N-(3′-Chloro-biphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isopropyl Ester

K.(S)-3-[N-(3′-Chloro-biphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydrox-propionicAcid

-   3-Hydroxyisoxazole-5-carboxylic acid (1.6 g, 12.1 mmol), HATU (4.6    g, 12.1 mmol) and DMF (31.2 mL) were combined and the resulting    mixture was stirred for 5 minutes at room temperature. DIPEA (4.0    mL, 23.1 mmol) and    (S)-3-[N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid isopropyl ester (3.7 g, 10.0 mmol) were added and the resulting    mixture was stirred until the reaction was complete (20 minutes).    The reaction was quenched with water, the mixture was diluted with    EtOAc, then washed with water and saturated aqueous NaCl. The    organic layer was dried, concentrated, and purified by flash    chromatography (50-90% EtOAc in hexanes). The clean fractions were    collected and concentrated. After evaporation, the ester compound J    was collected as a yellow solid TFA salt (3.5 g mg). MS m/z [M+H]⁺    calc'd for C₂₃H₂₄ClN₃O₆, 474.14; found 474.1.

A few grams of the ester compound J (350 mg) was dissolved in EtOH (17.6mL, 302 mmol), and 10.0 M aqueous NaOH (20.1 mL, 201 mmol) was added.The solids were filtered and the filtrate was acidified to pH=2 andextracted twice with DCM. The solution was dried over MgSO₄, filtratedand concentrated to give a yellow gum. The crude was purified (C18reverse phase column) The fractions were collected (1.4 g) and purifiedfurther to yield the acid compound K as a TFA salt (purity 100%). MS m/z[M+H]⁺ calc'd for C₂₀H₁₈ClN₃O₆, 432.09; found 432.1.

L.(R)-3-[N-(3′-Chloro-biphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicacid 2-fluoro-1-fluoromethyl-ethyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid (8 mg, 20 μmol) was dissolved in 1,3-difluoro-2-propanol (144 μL,1.9 mmol) and sonicated. A solution of 4 M HCl in dioxane (232 μL, 0.9mmol) was added and the resulting mixture was stirred at roomtemperature for 2 hours and at 50° C. for 1 hour and monitored forcompleteness. The mixture was then stirred overnight until the reactionwas complete, then evaporated under reduced pressure and purified bypreparative HPLC to yield the title compound as a TFA salt (6.3 mg;purity 95%). MS m/z [M+H]⁺ calc'd for C₂₃H₂₂ClF₂N₃O₆, 510.12; found510.1.

M.(R)-3-[N-(3′-Chloro-biphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid 2,2,3,3,3-pentafluoropropyl Ester

(R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid (8 mg, 20 μmol) was dissolved in 2,2,3,3,3-pentafluoro-1-propanol(0.2 mL, 1.9 mmol) and sonicated. A solution of 4 M HCl in dioxane (232μL, 0.9 mmol) was added and the resulting mixture was stirred until thereaction was complete ˜48 hours), then evaporated under reduced pressureand purified by preparative HPLC to yield the title compound as a TFAsalt (1.9 mg). MS m/z [M+H]⁺ calc'd for C₂₃H₁₉ClF₅N₃O₆, 564.09; found564.2.

Example 4

Following the procedures described in the examples herein, andsubstituting the appropriate starting materials and reagents, compoundshaving the following formula were prepared as TFA salts:

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 1 —OH Cl HC₁₉H₁₇Cl₂N₅O₄ 450.07 450.2 2 —OH —OH H C₁₉H₁₈ClN₅O₅ 432.10 432.4

-   1.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-chloro-2H-[1,2,4]triazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   2.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-hydroxy-2H-[1,2,4]triazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 3 —OH H H C₁₉H₁₈ClN₅O₄416.10 416.2

-   3.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 4 —OH H —OHC₁₉H₁₈ClN₅O₅ 432.10 432.4

-   4.    (R)-3-[1\1-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 5 —OH absent HC₁₈H₁₇ClN₆O₄ 417.10 417.4 6 —OCH₂CH(CH₃)₂ absent H C₂₂H₂₅ClN₆O₄ 473.16473.4 7 —OCH(CH₃)₂ absent H C₂₁H₂₃ClN₆O₄ 459.15 459.4 8 —OCH₂CH₃ absentH C₂₀H₂₁ClN₆O₄ 445.13 445.4

-   5.    (R)-3-[1\1-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   6.    (R)-3-[N-(3′-Chloro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isobutyl ester-   7.    (R)-3-[N-(3′-Chloro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isopropyl ester-   8.    (R)-3-[N-(3′-Chloro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 9 —OH

H C₂₅H₂₂ClN₅O₄ 492.14 492.2 10 —OH cyclopropyl H C₂₃H₂₃ClN₄O₄ 455.14455.2

-   9.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-pyridin-3-yl-1H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid (di-TFA salt)-   10.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-cyclopropyl-1H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 11 —OH

H C₂₅H₂₆ClN₅O₅ 512.16 512.4 12 —OH

H C₂₄H₂₄ClN₅O₅ 498.15 498.6 13 —OH —C(O)N(CH₃)₂ H C₂₃H₂₄ClN₅O₅ 486.15486.4 14 —OH

H C₂₅H₂₆ClN₅O₆ 528.16 528.2 15 —OH 2-chlorophenyl H C₂₆H₂₂Cl₂N₄O₄ 525.10525.4 16 —OH —C(O)N(CH₃)[CH₂CH(CH₃)₂] H C₂₆H₃₀ClN₅O₅ 528.19 528.2 17 —OH—C(O)N(CH₃)- H C₂₆H₂₈ClN₅O₅ 526.18 526.4 cyclopropyl 18 —OH

H C₂₄H₂₃ClFN₅O₅ 516.14 516.4 19 —OH 2-hydroxyphenyl H C₂₆H₂₃ClN₄O₅507.14 507.2 20 —OH 2-methoxyphenyl H C₂₇H₂₅ClN₄O₅ 521.15 521.2 21 —OH

H C₂₅H₂₂ClN₅O₄ 492.14 492.2 22 —OH —(CH₂)₃CH₃ H C₂₄H₂₇ClN₄O₄ 471.17471.2 23 —OH —COOH H C₂₁H₁₉ClN₄O₆ 459.10 459.2 24 —OH

H C₂₄H₂₁ClN₆O₄ 493.13 493.2 25 —OH —C(O)CH₃ H C₂₂H₂₁ClN₄O₅ 457.12 457.226 —OH —CH₂OCH₃ H C₂₂H₂₃ClN₄O₅ 459.14 459.2 27 —OH —C(CH₃)₂OH HC₂₃H₂₅ClN₄O₅ 473.15 473.2

-   11.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(pyrrolidine-1-carbonyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   12.    (R)-3-[N′-[5-(Azetidine-1-carbonyl)-2H-pyrazole-3-carbonyl]-N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   13.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-dimethylcarbamoyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   14.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-((R)-3-hydroxy-pyrrolidine-1-carbonyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   15.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(2-chlorophenyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   16.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(isobutyl-methyl-carbamoyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   17.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(cyclopropylmethyl-methyl-carbamoyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   18.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(3-fluoroazetidine-1-carbonyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   19.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(2-hydroxy-phenyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   20.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(2-methoxy-phenyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   21.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-pyridin-2-yl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid (di-TFA salt)-   22.    (R)-3-[N′-(5-Butyl-2H-pyrazole-3-carbonyl)-N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   23.    5-[N′—((R)-2-Carboxy-2-hydroxy-ethyl)-N′-(3′-chlorobiphenyl-4-ylmethyl)-hydrazinocarbonyl]-1H-pyrazole-3-carboxylic    acid-   24.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-pyrazin-2-yl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid (di-TFA salt)-   25.    (R)-3-[N′-(5-Acetyl-2H-pyrazole-3-carbonyl)-N-(3′-chlorobiphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   26.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(5-methoxymethyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   27.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[5-(1-hydroxy-1-methyl-ethyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 28 —OH phenyl HC₂₆H₂₂ClN₃O₅ 492.12 492.2

-   28.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(2-phenyl-oxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 29 —OH 2-chloro- HC₂₆H₂₁Cl₂N₃O₅ 526.09 526.4 phenyl 30 —OH 2-methoxy- H C₂₇H₂₄ClN₃O₆522.14 522.2 phenyl 31 —OH 2-fluoro- H C₂₆H₂₁ClFN₃O₅ 510.12 510.4 phenyl32 —OH —OCH₃ H C₂₁H₂₀ClN₃O₆ 446.10 446.0 33 —OCH₂CH₃ —OCH₃ HC₂₃H₂₄ClN₃O₆ 474.14 474.2

-   29.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[3-(2-chlorophenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   30.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[3-(2-methoxy-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   31.    (R)-3-{N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-[3-(2-fluorophenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   32.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-methoxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   33.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(3-methoxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 34 —OH —OH HC₂₁H₁₉ClN₄O₅ 443.10 443.2

-   34.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(2-hydroxy-pyrimidine-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 35 —OH —COOH HC₂₂H₁₉ClN₄O₆ 471.10 471.4 36 —OH —OH —OH C₂₁H₁₉ClN₄O₆ 459.10 459.4 37—OH H —OH C₂₁H₁₉ClN₄O₅ 443.10 443.2 38 —OH —COOH —OH C₂₂H₁₉ClN₄O₇ 487.09487.4

-   35.    6-[N′—((R)-2-Carboxy-2-hydroxy-ethyl)-N′-(3′-chlorobiphenyl-4-ylmethyl)-hydrazinocarbonyl]-pyrimidine-4-carboxylic    acid-   36.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(2,6-dihydroxy-pyrimidine-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   37.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(2-hydroxy-pyrimidine-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   38.    6-[N′—((R)-2-Carboxy-2-hydroxy-ethyl)-N′-(3′-chlorobiphenyl-4-ylmethyl)-hydrazinocarbonyl]-2-hydroxy-pyrimidine-4-carboxylic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 39 —OH ═O HC₂₀H₁₈ClN₃O₆ 432.09 432.4

-   39.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(2-oxo-2,3-dihydro-oxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 40 —OH —OH HC₂₀H₁₈ClN₃O₅S 448.07 448.0

-   40.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(2-hydroxy-thiazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ Formula calcd found 41 —OH H —OHC₂₃H₂₀ClN₅O₅ 482.12 482.0 42 —OH F H C₂₃H₁₉ClFN₅O₄ 484.11 484.4

-   41.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-benzotriazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   42.    (R)-3-[N-(3′-Chlorobiphenyl-4-ylmethyl)-N′-(4-fluoro-1H-benzotriazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

Example 5

Following the procedures described in the examples herein, andsubstituting the appropriate starting materials and reagents, compoundshaving the following formula were prepared as TFA salts:

 

MS m/z: [M + H]⁺ Ex. R³ R⁴ R⁶ Formula calcd found 1 —OH H 3′-FC₂₀H₁₈FN₃O₆ 416.12 416.2 2 —OH H 3′-CF₃ C₂₁H₁₈F₃N₃O₆ 466.11 466.2 3 —OHH 3′-OH C₂₀H₁₉N₃O₇ 414.12 414.4 4 —OH H 3′-CH₃ C₂₁H₂₁N₃O₆ 412.14 412.2 5—OH H 2′-OCH₃ C₂₁H₂₁N₃O₇ 428.14 428.2 6 —OH H 2′-OH C₂₀H₁₉N₃O₇ 414.12414.2 7 —OH H 2′-Cl C₂₀H₁₈ClN₃O₆ 432.09 432.4 8 —OH H 2′-F C₂₀H₁₈FN₃O₆416.12 416.4

-   1.    (R)-3-[N-(3′-Fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   2.    (R)-2-Hydroxy-3-[N′-(3-hydroxy-isoxazole-5-carbonyl)-N-(3′-trifluoromethyl-biphenyl-4-ylmethyl)-hydrazino]-propionic    acid-   3.    (S)-2-Hydroxy-3-[N-(3′-hydroxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-propionic    acid-   4.    (S)-2-Hydroxy-3-[N′-(3-hydroxy-isoxazole-5-carbonyl)-N-(3′-methyl-biphenyl-4-ylmethyl)-hydrazino]-propionic    acid-   5.    (R)-2-Hydroxy-3-[N′-(3-hydroxy-isoxazole-5-carbonyl)-N-(2′-methoxy-biphenyl-4-ylmethyl)-hydrazino]-propionic    acid-   6.    (R)-2-Hydroxy-3-[N-(2′-hydroxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-propionic    acid-   7.    (R)-3-[N-(2′-Chloro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   8.    (R)-3-[N-(2′-Fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R³ R⁴ R⁶ Formula calcd found 9 —C(O)CH₃ H 2′-OCH₃C₂₃H₂₄N₄O₆ 453.17 453.2

-   9.    (S)-3-[N′-(5-Acetyl-2H-pyrazole-3-carbonyl)-N-(2′-methoxy-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R³ R⁴ R⁶ Formula calcd found 10 absent H 2′-OCH₃C₁₉H₂₀N₆O₅ 413.15 413.4

-   10.    (R)-2-Hydroxy-3-[N-(2′-methoxy-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-propionic    acid

Preparation 6 Dipotassium 1H-tetrazole-5-carboxylate

A solution of potassium hydroxide (1.3 g, 23.2 mmol) in water (4.2 mL,230 mmol) was added to a solution of ethyl tetrazole-5-carboxylate (1.1g, 7.7 mmol) in EtOH (24 mL, 410 mmol). A solid product formedimmediately and was collected and washed with cold EtOH to yield thetitle compound (1.5 g).

Preparation 7 (R)-3-[N-(4-Bromobenzyl)-hydrazino]-2-hydroxy-propionicAcid Methyl Ester

(R)-3-[N-(4-Bromobenzyl)-N′-t-butoxycarbonyl-hydrazino]-2-hydroxy-propionicacid methyl ester (1.1 g, 2.8 mmol) was dissolved in MeCN (10 mL) and of4N HCl in dioxane (6 mL, 20 mmol). The mixture was stirred at roomtemperature until deprotection was complete (1 hour). The precipitatewas filtered and dried to yield the title compound (840 mg) as an HClsalt.

Preparation 8(R)-3-[N-(4-Bromobenzyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicAcid Methyl Ester

To a stirred solution of DMF (711 μL, 9.2 mmol) in MeCN (2 mL, 40 mmol)at 0° C., was slowly added a solution of oxalyl chloride (249 μL, 2.94mmol) in MeCN (500 μL, 9 mmol). After 10 minutes, dipotassium1H-tetrazole-5-carboxylate (241 mg, 1.3 mmol) was added and afterstirring for a further 15 minutes, was added to a solution of compound 1(240 mg, 0.8 mmol) in pyridine (9.6 mL, 120 mmol). The stirred reactionmixture was allowed to slowly warm to room temperature and stirred for20 minutes. The mixture was evaporated under reduced pressure to yieldthe title compound.

Preparation 9(R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionicAcid Ethyl Ester

(R)-3-[N-(4-Bromobenzyl)-N′-t-butoxycarbonyl-hydrazino]-2-hydroxy-propionicacid methyl ester (1.0 g, 2.5 mmol), 5-chloro-2-fluorophenylboronic acid(865 mg, 4.96 mmol), and K₂CO₃ (857 mg, 6.2 mmol), were combined in EtOH(30 mL, 500 mmol) and water (8 mL, 400 mmol), followed by the additionof SilicaCat° DPP-Pd (0.28 mmol/g loading; 886 mg, 248 μmol). Themixture was heated at 90° C. until the reaction was complete (2 hours).The precipitate was filtered off, and the filtrate was concentrated andpurified (Interchim reverse phase chromatography column; 30-95% MeCN inwater with 0.5% TFA). The clean fractions were collected, lyophilized,and combined with 4 M HCl in dioxane (8 mL, 30 mmol) and EtOH (10 mL,200 mmol). The resulting mixture was stirred at room temperature untilthe reaction was complete (7 hours). The mixture was concentrated toyield an oil, which was stirred in ether with few drops of EtOHovernight. The precipitate was filtered off and rinsed with ether toyield the title compound (140 mg).

Example 6 A.(R)-3-[N-(5′-Chloro-2′-fluorobiphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid

(R)-3-[N-(4-Bromobenzyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid methyl ester (60 mg, 0.2 mmol), 5-chloro-2-fluorophenylboronic acid(52.4 mg, 301 μmol), and K₂CO₃ (62.3 mg, 451 μmol) were combined in EtOH(0.8 mL) and water (0.2 mL), followed by the addition ofSilicaCat®DPP-Pd (0.28 mmol/g loading; 53.7 mg, 15 μmol). The mixturewas heated at 120° C. until the reaction was complete (30 minutes). Theprecipitate was filtered off, and 1 M aqueous LiOH (1.2 mL, 1.2 mmol)was added to the filtrate and stirred for 1 hour. The mixture wasevaporated under reduced pressure and purified by preparative HPLC toyield the title compound as a TFA salt (20 mg; purity 95%). MS m/z[M+H]⁺ calc'd for C₁₈H₁₆ClFN₆O₄, 435.09; found 435.4.

B.(R)-3-[N-(5′-Chloro-2′-fluorobiphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Ethyl Ester

Dipotassium 1H-tetrazole-5-carboxylate was prepared as follows: Asolution of potassium hydroxide (1.3 g, 23.2 mmol) in water (4.2 mL, 230mmol) was added to a solution of ethyl tetrazole-5-carboxylate (1.1 g,7.7 mmol) in EtOH (24 mL, 410 mmol). The solid product that formedimmediately was collected and washed with cold EtOH to yield dipotassium1H-tetrazole-5-carboxylate (1.5 g).

To a stirred solution of DMF (734 μL, 9.5 mmol) in MeCN (2 mL, 50 mmol)at 0° C., was slowly added a solution of oxalyl chloride (257 μL, 3.0mmol) in MeCN (500 μL, 9 mmol). After 10 minutes, dipotassium1H-tetrazole-5-carboxylate (249 mg, 1.3 mmol) was added and afterstirring for a further 15 minutes, was added to a solution of(R)-3-[N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionicacid ethyl ester (300 mg, 0.8 mmol) in MeCN (2 mL, 40 mmol) and pyridine(661 μL, 8.2 mmol). The mixture was stirred at 0° C. for 10 minutes thenevaporated under reduced pressure and purified (Interchim reverse phasechromatography column; elute from 55-75%, both peaks coeluted together)to yield the title compound (280 mg). A portion (80 mg) was furtherpurified by preparative HPLC to yield the title compound as a TFA salt(33 mg; purity 98%). MS m/z [M+H]⁺ calc'd for C₂₀H₂₀ClFN₆O₄, 463.12;found 463.4.

C.(R)-3-[N-(5′-Chloro-2′-fluorobiphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isopropyl Ester

(R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid (50 mg, 0.1 mmol) was dissolved in isopropyl alcohol (2 mL, 30mmol) then 4 M HCl in dioxane (0.8 mL, 3 mmol) was added. The resultingmixture was stirred at room temperature until the reaction was complete(˜17 hours). The mixture was evaporated under reduced pressure andpurified (Interchim C18 reverse phase column; 30-95% MeCN in water with0.05% TFA). The clean fractions were combined and lyophilized to yieldthe title compound as a TFA salt (43 mg; purity 98%). MS m/z [M+H]⁺calc'd for C₂₁H₂₂ClFN₆O₄, 477.14; found 477.2.

D.(R)-3-[N-(5′-Chloro-2′-fluorobiphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isobutyl Ester

(R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid (50 mg, 0.1 mmol) was dissolved in isobutyl alcohol (2 mL, 30 mmol)then 4 M HCl in dioxane (0.8 mL, 3 mmol) was added. The resultingmixture was stirred at room temperature until the reaction was complete(˜3 hours). The mixture was evaporated under reduced pressure andpurified (Interchim C18 reverse phase column; 30-95% MeCN in water with0.05% TFA). The clean fractions were combined and lyophilized to yieldthe title compound as a TFA salt (34 mg; purity 98%). MS m/z [M+H]⁺calc'd for C₂₂H₂₄ClFN₆O₄, 491.15; found 491.4.

Alternate Procedure

To a stirred solution of DMF (2.8 mL, 36.6 mmol) in MeCN (10 mL, 200mmol) at 0° C., was slowly added a solution of oxalyl chloride (267 μL,3.2 mmol) in MeCN (1.7 mL, 31.5 mmol). After 10 minutes, dipotassium1H-tetrazole-5-carboxylate (600 mg, 3 mmol was added and after stirringfor a further 15 minutes, was added to a solution of(R)-3-[N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionicacid ethyl ester (1000 mg, 3 mmol in pyridine (5.1 mL, 63.1 mmol). Themixture was stirred at 0° C. for 10 minutes then evaporated underreduced pressure. The dried material was then dissolved into EtOH (7.4mL, 126 mmol). A solution of 1 M aqueous LiOH (15.8 mL, 15.8 mmol) wasthen added and the resulting mixture was stirred at room temperature for30 minutes. The solution was then evaporated under reduced pressure andpurified (Interchim reverse phase column; 10-90% MeCN in water). Thepurified product was dissolved in isobutyl alcohol (29.1 mL, 315 mmol).A solution of 4.0 M HCl in 1,4-dioxane (7.9 mL, 31.5 mmol) was added,and the resulting mixture was stirred at room temperature for 1 hour,then at 30° C. for 1 hour. The solution was evaporated under reducedpressure and purified by preparative HPLC to yield the title compound asa TFA salt (186.6 mg).

Example 7 A.(R)-3-[N-(2′,5′-Dichlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]-triazole-4-carbonyl)-hydrazino]-2-hydroxypropionicAcid

1-Hydroxy-1H-1,2,3-triazole-4-carboxylic acid (42.6 mg, 330 μmol) andHATU (125 mg, 330 μmol) were combined in DMF (2 mL) and stirred for 5minutes at room temperature. DIPEA (86 μL, 495 μmol) and(R)-3-[N-(4-Bromobenzyl)-hydrazino]-2-hydroxy-propionic acid methylester (50 mg, 0.2 mmol) were added, and the resulting mixture wasstirred for 30 minutes. The mixture was evaporated under reducedpressure and the product dissolved in EtOH (0.8 mL, 10 mmol) and water(0.2 mL, 10 mmol). 2,5-Dichlorophenylboronic acid (57 mg, 297 μmol),K₂CO₃ (68 mg, 495 μmol), and SilicaCat®DPP-Pd (0.28 mmol/g loading; 58.9mg, 16.5 μmol) were added and the resulting mixture was heated at 120°C. for 10 minutes. The mixture was filtered, and 1 M aqueous LiOH (1.2mL, 1.2 mmol) was added to the filtrated. The mixture was stirred untilthe reaction was complete (1 hour), then vacuumed to dryness andpurified by preparative HPLC to yield the title compound as a TFA salt(14 mg; purity 95%). MS m/z [M+H]⁺ calc'd for C₁₉H₁₇Cl₂N₅O₅, 466.06;found 466.2.

B.(R)-3-[N-(2′,5′-Dichlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxypropionicAcid Heptyl Ester

(R)-3-[N-(2′,5′-Dichlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-1,2,3-triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionicacid (150 mg, 320 μmol) was dissolved in 1-heptanol (9.1 mL, 64.3 mmol).4 M HCl in dioxane (3.2 mL, 12.9 mmol) was added and the resultingmixture was stirred at room temperature overnight. The mixture wasevaporated under reduced pressure and purified by preparative HPLC toyield the title compound as a TFA salt (12 mg; purity 100%). MS m/z[M+H]⁺ calc'd for C₂₆H₃₁Cl₂N₅O₅, 564.17; found 564.2.

C.(R)-3-[N-(2′,5′-Dichlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isobutyl Ester

(R)-3-[N-(2′,5′-Dichlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-1,2,3-triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionicacid (150 mg, 320 μmol) was dissolved in isobutyl alcohol (8.9 mL, 96.5mmol). 4 M HCl in dioxane (3.2 mL, 12.9 mmol) was added and theresulting mixture was stirred at room temperature overnight. The mixturewas evaporated under reduced pressure and purified by preparative HPLCto yield the title compound as a TFA salt (28.5 mg; purity 100%). MS m/z[M+H]⁺ calc'd for C₂₃H₂₅Cl₂N₅O₅, 522.12; found 522.2.

D.(R)-3-[N-(2′,5′-Dichlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]-triazole-4-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isopropyl Ester

(R)-3-[N-(2′,5′-Dichlorobiphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-1,2,3-triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionicacid (150 mg, 320 μmol) was dissolved in isopropyl alcohol (4.9 mL, 64.3mmol). 4 M HCl in dioxane (3.2 mL, 12.9 mmol) was added and theresulting mixture was stirred at room temperature overnight. The mixturewas evaporated under reduced pressure and purified by preparative HPLCto yield the title compound as a TFA salt (4.7 mg; purity 100%). MS m/z[M+H]⁺ calc'd for C₂₂H₂₃Cl₂N₅O₅, 508.11; found 508.2.

Example 8

Following the procedures described in the examples herein, andsubstituting the appropriate starting materials and reagents, compoundshaving the following formula were prepared as TFA salts:

 

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found  1 —OH —OH H 22′-Me, C₂₁H₂₀ClN₃O₆ 446.10 446.4 5′-Cl  2 —OH —OH H 2 2′-OMe,C₂₁H₂₀ClN₃O₇ 462.10 462.2 5′-Cl  3 —OCH₂—CH₃ —OH H 2 2′-OMe,C₂₃H₂₄ClN₃O₇ 490.13 490.4 5′-Cl  4 —OH —OH H 2 2′-OMe, C₂₁H₂₀FN₃O₇446.13 446.4 5′-F  5 —OH —OH H 2 2′-OH, C₂₀H₁₈FN₃O₇ 432.11 432.4 5′-F  6—OH —OH H 2 2′-OH, C₂₀H₁₈ClN₃O₇ 448.08 448.0 5′-Cl  7 —OH —OH H 2 2′-OH,C₂₀H₁₈ClN₃O₇ 448.08 448.0 3′-Cl  8 —OH —OH H 2 2′-F, C₂₀H₁₇ClFN₃O₆450.08 450.2 5′-Cl  9 —OH —OCH₃ H 2 2′-F, C₂₁H₁₉ClFN₃O₆ 464.09 464.05′-Cl 10 —OCH₂—CH₃ —OCH₃ H 2 2′-F, C₂₃H₂₃ClFN₃O₆ 492.13 492.2 5′-Cl 11—OCH—(CH₃)₂ —OCH₃ H 2 2′-F, C₂₄H₂₅ClFN₃O₆ 506.14 506.4 5′-Cl 12—OCH₂—CH—(CH₃)₂ —OCH₃ H 2 2′-F, C₂₅H₂₇ClFN₃O₆ 520.16 520.2 5′-Cl 13 —OH

H 2 2′-F, 5′-Cl C₂₆H₂₀ClF₂N₃O₅ 528.11 528.0 14 —OH —CH₂—CH₃ H 2 2′-F,C₂₂H₂₁ClFN₃O₅ 462.12 462.0 5′-Cl 15 —OH

H 2 2′-F, 5′-Cl C₂₇H₂₃ClFN₃O₆ 540.13 540.2 16 —OH

H 2 2′-F, 5′-Cl C₂₆H₂₀Cl₂FN₃O₅ 544.08 544.0 17 —OH

H 2 2′-F, 5′-Cl C₂₆H₂₀Cl₂FN₃O₅ 544.08 544.0 18 —OH

H 2 2′-F, 5′-Cl C₂₆H₂₀ClF₂N₃O₅ 528.11 528.2 19 —O—CH₂—CH₃

H 2 2′-F, 5′-Cl C₂₈H₂₄ClF₂N₃O₅ 556.14 556.2 20

H 2 2′-F, 5′-Cl C₃₂H₃₁ClF₂N₄O₆ 641.19 641.2 21 —OH —OH H 2 2′-F,C₂₀H₁₇ClFN₃O₆ 450.08 450.2 3′-Cl 22 —OH —OH H 2 2′, 5′- C₂₀H₁₇Cl₂N₃O₆466.05 466.2 diCl 23 —OH —OH H 3 2′-F, C₂₁H₁₉ClFN₃O₆ 464.09 464.4 3′-Me,5′-Cl 24 —OH —OH H 2 3′-F, C₂₀H₁₇ClFN₃O₆ 450.08 450.2 5′-Cl 25 —OH —OH H2 3′,5′- C₂₀H₁₇Cl₂N₃O₆ 466.05 466.2 diCl 26 —OH —OH H 2 3′,5′-C₂₀H₁₇F₂N₃O₆ 434.11 434.4 diF 27 —OH —OH H 2 3′-OH, C₂₀H₁₈ClN₃O₇ 448.08448.0 5′-Cl 28 —OH —OH H 3 2′-Me, C₂₁H₁₉Cl₂N₃O₆ 480.07 480.2 3′,5′- diCl29 —OH —Cl H 2 2′-F, C₂₀H₁₆Cl₂FN₃O₅ 468.05 468.2 5′-Cl 30 —OH—CH₂CH—(CH₃)₂ H 2 2′-F, C₂₄H₂₅ClFN₃O₅ 490.15 490.2 5′-Cl 31 —OH—(CH₂)₂CH₃ H 2 2′-F, C₂₃H₂₃ClFN₃O₅ 476.13 476.2 5′-Cl 32 —OH —CH(CH₃)₂ H2 2′-F, C₂₃H₂₃ClFN₃O₅ 476.13 476.4 5′-Cl 33 —OH —C(CH₃)₃ H 2 2′-F,C₂₄H₂₅ClFN₃O₅ 490.15 489.8 5′-Cl

-   1.    (R)-3-[N-(5′-Chloro-2′-methyl-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   2.    (R)-3-[N-(5′-Chloro-2′-methoxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   3.    (R)-3-[N-(5′-Chloro-2′-methoxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester-   4.    (R)-3-[N-(5′-Fluoro-2′-methoxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   5.    (S)-3-[N-(5′-Fluoro-2′-hydroxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   6.    (S)-3-[N-(5′-Chloro-2′-hydroxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   7.    (R)-3-[N-(3′-Chloro-2′-hydroxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   8.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   9.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-methoxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   10.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-methoxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester-   11.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-methoxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isopropyl ester-   12.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-methoxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isobutyl ester-   13.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[3-(3-fluoro-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   14.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-ethyl-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   15.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[3-(2-methoxy-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   16.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[3-(3-chloro-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   17.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[3-(2-chloro-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   18.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[3-(2-fluoro-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   19.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[3-(2-fluoro-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid ethyl ester-   20.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[3-(2-fluoro-phenyl)-isoxazole-5-carbonyl]-hydrazino}-2-hydroxy-propionic    acid 2-morpholin-4-yl-ethyl ester-   21.    (R)-3-[N-(3′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   22.    (S)-[4N-(2′,5′-Dichloro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   23.    (S)-3-[N-(5′-Chloro-2′-fluoro-3′-methyl-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   24.    (S)-3-[N-(5′-Chloro-3′-fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   25.    (R)-3-[N-(3′,5′-Dichloro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   26.    (S)-3-[N-(3′,5′-Difluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   27.    (S)-3-[N-(5′-Chloro-3′-hydroxy-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   28.    (S)-3-[N-(3′,5′-Dichloro-2′-methyl-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   29.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-chloro-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   30.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-isobutyl-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   31.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-propyl-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   32.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-isopropyl-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   33.    (R)-3-[N′-(3-tert-Butyl-isoxazole-5-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 34 —OH

H 2 2′-F, 5′-Cl C₂₅H₂₀ClFN₄O₅ 511.11 511.2

-   34.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-pyridin-3-yl-isoxazole-3-carbonyl)-hydrazino]-2-hydr    oxy-propionic acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 35 —OH—C(O)N(CH₃)₂ H 2 2′-F, C₂₃H₂₃ClFN₅O₅ 504.14 504.2 5′-Cl 36 —OH

H 2 2′-F, 5′-Cl C₂₅H₂₁ClFN₅O₄ 510.13 510.2 37 —OCH₂CH₃

H 2 2′-F, 5′-Cl C₂₇H₂₅ClFN₅O₄ 538.16 538.4 38 —OH

H 2 2′-F, 5′-Cl C₂₆H₂₂ClFN₄O₅ 525.13 525.2 39 —OH

H 2 2′-F, 5′-Cl C₂₇H₂₄ClFN₄O₅ 539.14 539.2 40 —OH —C(CH₃)₂OH H 2 2′-F,C₂₃H₂₄ClFN₄O₅ 491.14 491.2 5′-Cl 41 —OH

H 2 2′-F, 5′-Cl C₂₆H₂₀Cl₃FN₄O₄ 577.05 577.0 42 —OH —(CH₂)₃CH₃ H 2 2′-F,C₂₄H₂₆ClFN₄O₄ 489.16 489.2 5′-Cl 43 —OH cyclopropyl H 2 2′-F,C₂₃H₂₂ClFN₄O₄ 473.13 473.2 5′-Cl 44 —OH —CH(CH₃)₂ H 2 2′-F,C₂₃H₂₄ClFN₄O₄ 475.15 475.2 5′-Cl 45 —OH —C(O)CH₃ H 2 2′-F, C₂₂H₂₀ClFN₄O₅475.11 475.2 5′-Cl 46 —OCH₂CH₃ —C(O)CH₃ H 2 2′-F, C₂₄H₂₄ClFN₄O₅ 503.14503.2 5′-Cl 47 —OH —C(O)CH₃ H 2 2′-Me, C₂₃H₂₃ClN₄O₅ 471.14 471.4 5′-Cl48 —OH —C(O)CH₃ H 2 2′, 5′- C₂₂H₂₀Cl₂N₄O₅ 491.08 491.0 diCl 49 —OH

H 2 2′-F, 5′-Cl C₂₈H₂₅ClFN₅O₆ 582.15 582.2

-   35.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-dimethylcarbamoyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   36.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-pyridin-2-yl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   37.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-pyridin-2-yl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester-   38.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N-[5-(2-hydroxy-phenyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   39.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[5-(2-methoxy-phenyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   40.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[5-(1-hydroxy-1-methyl-ethyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   41.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[5-(2,5-dichloro-phenyl)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   42.    (R)-3-[N′-(5-Butyl-2H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   43.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-cyclopropyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   44.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-isopropyl-2H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   45.    (S)-3-[N′-(5-Acetyl-2H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   46.    (S)-3-[N′-(5-Acetyl-2H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester-   47.    (S)-3-[N′-(5-Acetyl-2H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-methyl-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   48.    (S)-3-[N′-(5-Acetyl-2H-pyrazole-3-carbonyl)-N-(2′,5′-dichloro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   49.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[5-(2-methoxy-benzoylamino)-2H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 50 —OH

H 2 2′-F, 5′-Cl C₂₄H₂₀ClFN₆O₄ 511.12 511.2 51 —OH —OH

2 2′-F, 5′-Cl C₂₅H₂₁ClFN₅O₅ 526.12 526.4 52 —OH —OH

2 2′-F, 5′-Cl C₂₆H₂₁ClF₂N₄O₅ 543.12 543.6 53 —OH cyclo- —CH₂COOH 2 2′-F,C₂₅H₂₄ClFN₄O₆ 531.14 531.0 propyl 5′-Cl 54 —OH —CH(CH₃)₂ —CH₂COOH 22′-F, C₂₅H₂₆ClFN₄O₆ 533.15 533.2 5′-Cl 55 —OH —(CH₂)₃CH₃ —CH₂COOH 22′-F, C₂₆H₂₈ClFN₄O₆ 547.17 547.0 5′-Cl 56 —OH —C(CH₃)₂OH —CH₂COOH 22′-F, C₂₅H₂₆ClFN₄O₇ 549.15 549.0 5′-Cl 57 —OH —OCH₂CH₃ H 2 2′-F,C₂₂H₂₂ClFN₄O₅ 477.13 477.2 5′-Cl

-   50.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-pyrazin-2-yl-1H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   51.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-hydroxy-1-pyridin-2-yl-1H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   52.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[1-(2-fluoro-phenyl)-5-hydroxy-1H-pyrazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   53.    (R)-3-[N′-(1-Carboxymethyl-5-cyclopropyl-1H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   54.    (R)-3-[N′-(1-Carboxymethyl-5-isopropyl-1H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   55.    (R)-3-[N′-(5-Butyl-1-carboxymethyl-1H-pyrazole-3-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   56.    (R)-3-[N′-[1-Carboxymethyl-5-(1-hydroxy-1-methyl-ethyl)-1H-pyrazole-3-carbonyl]-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   57.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-ethoxy-1H-pyrazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 58 —OH ═O H 22′-F, 5′-Cl C₂₁H₁₈ClFN₄O₅ 461.10 461.2

-   58.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(6-oxo-1,6-dihydro-pyridazine-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 59 —OH absent H 22′-Me, 5′-Cl C₁₉H₁₉ClN₆O₄ 431.12 431.2 60 —OH absent H 2 2′, 5′-diClC₁₈H₁₆Cl₂N₆O₄ 451.06 451.2 61 —OCH₂CH(CH₃)₂ absent H 2 2′, 5′-diClC₂₂H₂₄Cl₂N₆O₄ 507.12 507.2 62 —OCH(CH₃)₂ absent H 2 2′, 5′-diClC₂₁H₂₂Cl₂N₆O₄ 493.11 493.4 63 —OCH₂CH₃ absent H 2 2′, 5′-diClC₂₀H₂₀Cl₂N₆O₄ 479.09 479.2

-   59.    (R)-3-[N-(5′-Chloro-2′-methyl-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   60.    (R)-3-[N-(2′,5′-Dichloro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   61.    (R)-3-[N-(2′,5′-Dichloro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isobutyl ester-   62.    (R)-3-[N-(2′,5′-Dichloro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isopropyl ester-   63.    (R)-3-[N-(2′,5′-Dichloro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 64 —OH ═O phenyl2 2′-F, C₂₅H₂₁ClFN₅O₅ 526.12 526.0 5′-Cl 65 —OH ═O 4-fluoro- 2 2′-F,C₂₅H₂₀ClF₂N₅O₅ 544.11 543.1 phenyl 5′-Cl 66 —OH ═O 2-chloro- 2 2′-F,C₂₅H₂₀Cl₂FN₅O₅ 560.08 560.1 phenyl 5′-Cl 67 —OH ═O 3-chloro- 2 2′-F,C₂₅H₂₀Cl₂FN₅O₅ 560.08 559.6 phenyl 5′-Cl

-   64.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-oxo-1-phenyl-4,5-dihydro-1H-[1,2,4]triazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   65.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[1-(4-fluoro-phenyl)-5-oxo-4,5-dihydro-1H-[1,2,4]triazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   66.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[1-(2-chloro-phenyl)-5-oxo-4,5-dihydro-1H-[1,2,4]triazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid-   67.    (R)-3-{N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-[1-(3-chloro-phenyl)-5-oxo-4,5-dihydro-1H-[1,2,4]triazole-3-carbonyl]-hydrazino}-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 68 —OH —CH₃ H 22′-F, 5′-Cl C₂₄H₂₁ClFN₅O₄ 498.12 498.2 69 —OH Cl H 2 2′-F, 5′-ClC₂₃H₁₈Cl₂FN₅O₄ 518.07 518.0 70 —OCH₂CH₃ Cl H 2 2′-F, 5′-ClC₂₅H₂₂Cl₂FN₅O₄ 546.10 546.2 71 —OCH—(CH₃)₂ Cl H 2 2′-F, 5′-ClC₂₆H₂₄Cl₂FN₅O₄ 560.12 560.2 72 —OCH₂CH(CH₃)₂ Cl H 2 2′-F, 5′-ClC₂₇H₂₆Cl₂FN₅O₄ 574.13 574.0 73 —OH F H 2 2′-F, 5′-Cl C₂₃H₁₈ClF₂N₅O₄502.10 502.2

-   68.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(7-methyl-3H-benzotriazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   69.    (R)-3-[N′-(7-Chloro-3H-benzotriazole-5-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid-   70.    (R)-3-[N′-(7-Chloro-3H-benzotriazole-5-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester-   71.    (R)-3-[N′-(7-Chloro-3H-benzotriazole-5-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid isopropyl ester-   72.    (R)-3-[N′-(7-Chloro-3H-benzotriazole-5-carbonyl)-N-(5′-chloro-2′-fluoro-biphenyl-4-ylmethyl)-hydrazino]-2-hydroxy-propionic    acid isobutyl ester-   73.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(7-fluoro-3H-benzotriazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 74 —OH ═O H 22′-F, 5′-Cl C₂₀H₁₇ClFN₃O₆ 450.08 450.0

-   74.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(2-oxo-2,3-dihydro-oxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 75 —OH H H 22′-F, 5′-Cl C₁₉H₁₇ClFN₅O₄ 434.10 434.2

-   75.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 76 —OH H —OH 22′-F, C₁₉H₁₇ClFN₅O₅ 450.09 450.2 5′-Cl 77 —OCH₂CH₃ H H 2 2′-F,C₂₁H₂₁ClFN₅O₄ 462.13 462.2 5′-Cl 78 —OCH(CH₃)₂ H H 2 2′-F, C₂₂H₂₃ClFN₅O₄476.14 476.2 5′-Cl 79 —OCH₂—CH(CH₃)₂ H H 2 2′-F, C₂₃H₂₅ClFN₅O₄ 490.16490.2 5′-Cl 80 —OH H —OH 2 2′-Me, C₂₀H₂₀ClN₅O₅ 446.12 446.2 5′-Cl 81 —OHH —OH 2 3′, 5′- C₁₉H₁₇Cl₂N₅O₅ 466.06 466.2 diCl

-   76.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   77.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid ethyl ester-   78.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isopropyl ester-   79.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isobutyl ester-   80.    (R)-3-[N-(5′-Chloro-2′-methyl-biphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   81.    (R)-3-[N-(3′,5′-Dichloro-biphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 82 —OH Cl H 22′-F, 5′-Cl C₁₉H₁₆Cl₂FN₅O₄ 468.06 468.0

-   82.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(5-chloro-1H-[1,2,4]triazole-3-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R¹ R³ R⁴ b R⁶ Formula calcd found 83 —OH —OH H 22′-F, 5′-Cl C₂₀H₁₇ClFN₃O₅S 466.06 466.0 84 —OCH₂CH(CH₃)₂ —OH H 2 2′-F,5′-Cl C₂₄H₂₅ClFN₃O₅S 522.12 522.4

-   83.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(2-hydroxy-thiazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   84.    (R)-3-[N-(5′-Chloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(2-hydroxy-thiazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid isobutyl ester

Preparation 10(R)-3-[N-bromo-2-fluoro-benzyl)-hydrazino]-2-hydroxy-propionic acidmethyl ester

4-Bromo-2-fluorobenzyl bromide (5.0 g, 19 mmol) and DIPEA (3.3 mL, 18.7mmol) were dissolved in DMF (20 mL). t-Butyl carbazate (7.4 g, 56.0mmol) was added and the mixture was stirred at room temperature untilthe reaction was complete. The mixture was partially concentrated, thenthe residue was partitioned between EtOAc and a saturated aqueous NaHCO₃solution. The EtOAc layer was then dried over Na₂SO₄ and concentrated.The crude product was purified by flash chromatography to yield compound1 (4.7 g).

Compound 1 (1.9 g, 6.3 mmol) was dissolved in isopropyl alcohol (30 mL).Methyl (2R)-glycidate (3.3 mL, 37.3 mmol) was added and the mixture wasrefluxed at 90° C. until the reaction was complete (˜2 days). Themixture was concentrated to yield compound 2 (4.7 g).

Compound 2 was dissolved in 1:1 EtOH and 4N HCl in dioxane and stirredovernight. The mixture was then concentrated to yield the title compound(330 mg).

Example 9 A.(R)-3-[N-(3′-Chloro-3-fluorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid

3-Hydroxyisoxazole-5-carboxylic acid (24.1 mg, 186 μmol) was combinedwith HATU (70.9 mg, 186 μmol) in DMF (2 mL) and stirred for 5 minutes atroom temperature. DIPEA (54 μL, 311 μmol) and(R)-3-[N-(4-bromo-2-fluoro-benzyl)-hydrazino]-2-hydroxy-propionic acidmethyl ester (50 mg, 0.2 mmol) were added and the resulting mixture wasstirred for 10 minutes. The mixture was evaporated under reducedpressure and the residue was diluted with EtOAc, and washed with waterand saturated aqueous NaCl. The organic layer was separated andconcentrated. 3-Chlorophenylboronic acid (43.8 mg, 280 μmol), K₂CO₃ (65mg, 467 μmol), EtOH (0.8 mL), and water (0.2 mL) were added, followed bySilicaCat®Pd(0) (0.09 mmol/g loading; 121 mg, 11 μmol). The mixture washeated at 120° C. until the reaction was complete (10 minutes). Themixture was filtered, concentrated and purified by preparative HPLC toyield the title compound as a TFA salt (9.7 mg; purity 95%). MS m/z[M+H]⁺ calc'd for C₂₀H₁₇ClFN₃O₆, 450.08; found 450.2.

B.(R)-3-[N-(3′-Chloro-3-fluorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isobutyl Ester

(R)-3-[N-(3′-Chloro-3-fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid (75 mg, 0.2 mmol) was dissolved in isobutyl alcohol (3 mL, 30 mmol)and 4 M HCl in dioxane (1 mL, 4 mmol) was added. The mixture was stirredat room temperature until the reaction was complete (˜3 hours), thenevaporated under reduced pressure and purified by preparative HPLC toyield the title compound as a TFA salt (26 mg; purity 95%). MS m/z[M+H]⁺ calc'd for C₂₄H₂₅ClFN₃O₆, 506.14; found 506.

C.(R)-3-[N-(3′-Chloro-3-fluorobiphenyl-4-ylmethyl)-N′-(3-hydroxyisoxazole-5-carbonyl)-hydrazino]-2-hydroxypropionicAcid Isopropyl Ester

(R)-3-[N-(3′-Chloro-3-fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionicacid (75 mg, 0.2 mmol) was dissolved in isopropyl alcohol (2 mL, 20mmol) and 4 M HCl in dioxane (1 mL, 4 mmol) was added. The mixture wasstirred at room temperature until the reaction was complete (˜3 hours),then evaporated under reduced pressure and purified by preparative HPLCto yield the title compound as a TFA salt (20 mg; purity 95%). MS m/z[M+H]⁺ calc'd for C₂₃H₂₃ClFN₃O₆, 492.13; found 492.2.

Example 10

Following the procedures described in the examples herein, andsubstituting the appropriate starting materials and reagents, compoundshaving the following formula were prepared, either as the parentcompound or as a TFA salt:

MS m/z: [M + H]⁺ Ex. R³ R⁴ a R⁵ b R⁶ Formula calcd found 1 —OH H 1 3-F 0— C₂₀H₁₈FN₃O₆ 416.12 416.7 2 —OH H 1 3-CN 1 3′-Cl C₂₁H₁₇ClN₄O₆ 457.08457.4 3 —OH H 1 2-Cl 1 3′-Cl C₂₀H₁₇Cl₂N₃O₆ 466.05 466.2 4 —OH H 1 3-F 22′-F, C₂₀H₁₆ClF₂N₃O₆ 468.07 468.2 5′-Cl 5 —OH H 1 3-F 2 2′-F,C₂₀H₁₆ClF₂N₃O₆ 468.07 468.2 5′-Cl 6 —OH H 1 2-F 1 3′-Cl C₂₀H₁₇ClFN₃O₆450.08 450.2 7 —OH H 1 3-Cl 2 2′-F, C₂₀H₁₆Cl₂FN₃O₆ 484.04 484.4 5′-Cl

-   1.    (R)-3-[N-(3-Fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   2.    (R)-3-[N-(3′-Chloro-3-cyano-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   3.    (R)-3-[N-(2,3′-Dichloro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   4.    (R)-3-[N-(5′-Chloro-3,2′-difluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   5.    (R)-3-[N-(5′-Chloro-3,2′-difluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   6.    (R)-3-[N-(3′-Chloro-2-fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   7.    (R)-3-[N-(3,5′-Dichloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(3-hydroxy-isoxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R³ R⁴ a R⁵ b R⁶ Formula calcd found 8 absent H 13-F 1 3′-Cl C₁₈H₁₆ClFN₆O₄ 435.09 435.2

-   8.    (R)-3-[N-(3′-Chloro-3-fluoro-biphenyl-4-ylmethyl)-N′-(1H-tetrazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R³ R⁴ a R⁵ b R⁶ Formula calcd found  9 H —OH 1 3-F1 3′-Cl C₁₉H₁₇ClFN₅O₅ 450.09 450.2 10 H —OH 1 3-Cl 2 2′-F,C₁₉H₁₆Cl₂FN₅O₄ 468.06 468.2 5′-Cl 11 H —OH 1 3-Cl 1 3′-Cl C₁₉H₁₇Cl₂N₅O₄450.07 452.0

-   9.    (R)-3-[N-(3′-Chloro-3-fluoro-biphenyl-4-ylmethyl)-N′-(1-hydroxy-1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   10.    (R)-3-[N-(3,5′-Dichloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid-   11.    (R)-3-[N-(3,3′-Dichloro-biphenyl-4-ylmethyl)-N′-(1H-[1,2,3]triazole-4-carbonyl)-hydrazino]-2-hydroxy-propionic    acid

MS m/z: [M + H]⁺ Ex. R³ R⁴ a R⁵ b R⁶ Formula calcd found 12 ═O H 1 3-Cl2 2′-F, 5′-Cl C₂₀H₁₆Cl₂FN₃O₆ 484.04 484.0

-   12.    (R)-3-[N-(3,5′-Dichloro-2′-fluoro-biphenyl-4-ylmethyl)-N′-(2-oxo-2,3-dihydro-oxazole-5-carbonyl)-hydrazino]-2-hydroxy-propionic    acid (parent)

Assay 1 In vitro Assays for the Quantitation of Inhibitor Potencies(IC₅₀) at Human and Rat NEP, and Human ACE

The inhibitory activities of compounds at human and rat neprilysin (EC3.4.24.11; NEP) and human angiotensin converting enzyme (ACE) weredetermined using in vitro assays as described below.

Extraction of NEP Activity from Rat Kidneys

Rat NEP was prepared from the kidneys of adult Sprague Dawley rats.Whole kidneys were washed in cold phosphate buffered saline (PBS) andbrought up in ice-cold lysis buffer (1% Triton X-114, 150 mM NaCl, 50 mMtris(hydroxymethyl) aminomethane (Tris) pH 7.5; Bordier (1981) J. Biol.Chem. 256:1604-1607) in a ratio of 5 mL of buffer for every gram ofkidney. Samples were homogenized on ice using a polytron hand heldtissue grinder. Homogenates were centrifuged at 1000×g in a swingingbucket rotor for 5 minutes at 3° C. The pellet was resuspended in 20 mLof ice cold lysis buffer and incubated on ice for 30 minutes. Samples(15-20 mL) were then layered onto 25 mL of ice-cold cushion buffer (6%w/v sucrose, 50 mM pH 7.5 Tris, 150 mM NaCl, 0.06%, Triton X-114),heated to 37° C. for 3-5 minutes and centrifuged at 1000×g in a swingingbucket rotor at room temperature for 3 minutes. The two upper layerswere aspirated off, leaving a viscous oily precipitate containing theenriched membrane fraction. Glycerol was added to a concentration of 50%and samples were stored at −20° C. Protein concentrations werequantitated using a BCA detection system with bovine serum albumin (BSA)as a standard.

Enzyme Inhibition Assays

Recombinant human NEP and recombinant human ACE were obtainedcommercially (R&D Systems, Minneapolis, Minn., catalog numbers 1182-ZNand 929-ZN, respectively). The fluorogenic peptide substrateMca-D-Arg-Arg-Leu-Dap-(Dnp)-OH (Medeiros et al. (1997) Braz. J. Med.Biol. Res. 30:1157-62; Anaspec, San Jose, Calif.) andAbz-Phe-Arg-Lys(Dnp)-Pro-OH (Araujo et al. (2000) Biochemistry39:8519-8525; Bachem, Torrance, Calif.) were used in the NEP and ACEassays respectively.

The assays were performed in 384-well white opaque plates at 37° C.using the fluorogenic peptide substrates at a concentration of 10 μM inAssay Buffer (NEP: 50 mM HEPES, pH 7.5, 100 mM NaCl, 0.01% polyethyleneglycol sorbitan monolaurate (Tween-20), 10 μM ZnSO₄; ACE: 50 mM HEPES,pH 7.5, 100 mM NaCl, 0.01% Tween-20, 1 μM ZnSO₄). The respective enzymeswere used at concentrations that resulted in quantitative proteolysis of1 μM of substrate after 20 minutes at 37° C.

Test compounds were assayed over the range of concentrations from 10 μMto 20 pM. Test compounds were added to the enzymes and incubated for 30minute at 37° C. prior to initiating the reaction by the addition ofsubstrate. Reactions were terminated after 20 minutes of incubation at37° C. by the addition of glacial acetic acid to a final concentrationof 3.6% (v/v).

Plates were read on a fluorometer with excitation and emissionwavelengths set to 320 nm and 405 nm, respectively Inhibition constantswere obtained by nonlinear regression of the data using the equation(GraphPad Software, Inc., San Diego, Calif.):

ν=ν₀/[1+(I/K′)]

where ν is the reaction rate, ν₀ is the uninhibited reaction rate, I isthe inhibitor concentration and K′ is the apparent inhibition constant.

Compounds of the invention were tested in this assay and found to havepK_(i) values at human NEP as follows. In general, either the prodrugcompounds did not inhibit the enzyme in this in vitro assay, or theprodrugs were not tested (n.d.) since activity would not be expected.

Ex. pK_(i) 1   ≧9.0 2-1  8.0-8.9 2-2  8.0-8.9 2-3  8.0-8.9 2-4  7.0-7.92-5  7.0-7.9 2-6  8.0-8.9 2-7  7.0-7.9 2-8  8.0-8.9 2-9  8.0-8.9 2-108.0-8.9 2-11 8.0-8.9 2-12 8.0-8.9 2-13 8.0-8.9 2-14 7.0-7.9 2-15 8.0-8.92-16 7.0-7.9 2-17 7.0-7.9 2-18 8.0-8.9 2-19 8.0-8.9 2-20 6.0-6.9 2-217.0-7.9 2-22 6.0-6.9 2-23 6.0-6.9 2-24 6.0-6.9 2-25 6.0-6.9 3A n.d. 3B≧9.0 3C n.d. 3D n.d. 3E n.d. 3F n.d. 3G n.d. 3H n.d. 3I  n.d. 3J  n.d.3K ≧9.0 3L n.d.  3M n.d. 4-1  8.0-8.9 4-2  8.0-8.9 4-3  8.0-8.9 4-4 ≧9.0 4-5  ≧9.0 4-6  n.d. 4-7  n.d. 4-8  n.d. 4-9  8.0-8.9 4-10 8.0-8.94-11 ≧9.0 4-12 ≧9.0 4-13 ≧9.0 4-14 ≧9.0 4-15 ≧9.0 4-16 ≧9.0 4-17 ≧9.04-18 ≧9.0 4-19 8.0-8.9 4-20 8.0-8.9 4-21 8.0-8.9 4-22 ≧9.0 4-23 ≧9.04-24 8.0-8.9 4-25 ≧9.0 4-26 8.0-8.9 4-27 8.0-8.9 4-28 7.0-7.9 4-29 ≧9.04-30 8.0-8.9 4-31 8.0-8.9 4-32 8.0-8.9 4-33 n.d. 4-34 ≧9.0 4-35 ≧9.04-36 7.0-7.9 4-37 7.0-7.9 4-38 ≧9.0 4-39 8.0-8.9 4-40 8.0-8.9 4-418.0-8.9 4-42 8.0-8.9 5-1  8.0-8.9 5-2  7.0-7.9 5-3  8.0-8.9 5-4  ≧9.05-5  8.0-8.9 5-6  8.0-8.9 5-7  8.0-8.9 5-8  8.0-8.9 5-9  8.0-8.9 5-108.0-8.9 6A ≧9.0 6B n.d. 6C n.d. 6D n.d. 7A ≧9.0 7B n.d. 7C n.d. 7D n.d.8-1  ≧9.0 8-2  ≧9.0 8-3  n.d. 8-4  8.0-8.9 8-5  8.0-8.9 8-6  8.0-8.98-7  8.0-8.9 8-8  ≧9.0 8-9  ≧9.0 8-10 n.d. 8-11 n.d. 8-12 n.d. 8-13 ≧9.08-14 ≧9.0 8-15 ≧9.0 8-16 ≧9.0 8-17 ≧9.0 8-18 ≧9.0 8-19 n.d 8-20 n.d 8-218.0-8.9 8-22 ≧9.0 8-23 8.0-8.9 8-24 8.0-8.9 8-25 ≧9.0 8-26 7.0-7.9 8-27≧9.0 8-28 7.0-7.9 8-29 8.0-8.9 8-30 ≧9.0 8-31 ≧9.0 8-32 ≧9.0 8-338.0-8.9 8-34 8.0-8.9 8-35 ≧9.0 8-36 ≧9.0 8-37 n.d. 8-38 ≧9.0 8-39 ≧9.08-40 ≧9.0 8-41 ≧9.0 8-42 ≧9.0 8-43 ≧9.0 8-44 ≧9.0 8-45 ≧9.0 8-46 n.d.8-47 8.0-8.9 8-48 8.0-8.9 8-49 ≧9.0 8-50 ≧9.0 8-51 8.0-8.9 8-52 8.0-8.98-53 8.0-8.9 8-54 8.0-8.9 8-55 8.0-8.9 8-56 8.0-8.9 8-57 8.0-8.9 8-58≧9.0 8-59 ≧9.0 8-60 ≧9.0 8-61 n.d. 8-62 n.d. 8-63 n.d. 8-64 ≧9.0 8-658.0-8.9 8-66 8.0-8.9 8-67 ≧9.0 8-68 8.0-8.9 8-69 ≧9.0 8-70 n.d. 8-71n.d. 8-72 n.d. 8-73 ≧9.0 8-74 ≧9.0 8-75 ≧9.0 8-76 ≧9.0 8-77 n.d. 8-78n.d. 8-79 n.d. 8-80 ≧9.0 8-81 7.0-7.9 8-82 ≧9.0 8-83 ≧9.0 8-84 n.d. 9A≧9.0 9B n.d. 9C n.d. 10-1  8.0-8.9 10-2  8.0-8.9 10-3  ≧9.0 10-4  ≧9.010-5  ≧9.0 10-6  ≧9.0 10-7  ≧9.0 10-8  8.0-8.9 10-9  ≧9.0 10-10  ≧9.010-11  ≧9.0 10-12  n.d. n.d. = not determined

Assay 2 Pharmacodynamic (PD) assay for ACE and NEP Activity inAnesthetized Rats

Male, Sprague Dawley, normotensive rats are anesthetized with 120 mg/kg(i.p.) of inactin. Once anesthetized, the jugular vein, carotid artery(PE 50 tubing) and bladder (flared PE 50 tubing) catheters arecannulated and a tracheotomy is performed (Teflon Needle, size 14 gauge)to facilitate spontaneous respiration. The animals are then allowed a 60minute stablization period and kept continuously infused with 5 mL/kg/hof saline (0.9%) throughout, to keep them hydrated and ensure urineproduction. Body temperature is maintained throughout the experiment byuse of a heating pad. At the end of the 60 minute stabilization period,the animals are dosed intravenously (i.v.) with two doses of AngI (1.0μg/kg, for ACE inhibitor activity) at 15 minutes apart. At 15 minutespost-second dose of AngI, the animals are treated with vehicle or testcompound. Five minutes later, the animals are additionally treated witha bolus i.v. injection of atrial natriuretic peptide (ANP; 30 μg/kg).Urine collection (into pre-weighted eppendorf tubes) is startedimmediately after the ANP treatment and continued for 60 minutes. At 30and 60 minutes into urine collection, the animals are re-challenged withAngI. Blood pressure measurements are done using the Notocord system(Kalamazoo, Mich.). Urine samples are frozen at −20° C. until used forthe cGMP assay. Urine cGMP concentrations are determined by EnzymeImmuno Assay using a commercial kit (Assay Designs, Ann Arbor, Mich.,Cat. No. 901-013). Urine volume is determined gravimetrically. UrinarycGMP output is calculated as the product of urine output and urine cGMPconcentration. ACE inhibition is assessed by quantifying the %inhibition of pressor response to AngI. NEP inhibition is assessed byquantifying the potentiation of ANP-induced elevation in urinary cGMPoutput.

Assay 3 In Vivo Evaluation of Antihypertensive Effects in the ConsciousSHR Model of Hypertension

Spontaneously hypertensive rats (SHR, 14-20 weeks of age) are allowed aminimum of 48 hours acclimation upon arrival at the testing site withfree access to food and water. For blood pressure recording, theseanimals are surgically implanted with small rodent radiotransmitters(telemetry unit; DSI Models TA11PA-C40 or C50-PXT, Data Science Inc.,USA). The tip of the catheter connected to the transmitter is insertedinto the descending aorta above the iliac bifurcation and secured inplace with tissue adhesive. The transmitter is kept intraperitoneallyand secured to the abdominal wall while closing of the abdominalincision with a non-absorbable suture. The outer skin is closed withsuture and staples. The animals are allowed to recover with appropriatepost operative care. On the day of the experiment, the animals in theircages are placed on top of the telemetry receiver units to acclimate tothe testing environment and baseline recording. After at least of 2hours baseline measurement is taken, the animals are then dosed withvehicle or test compound and followed out to 24 hours post-dose bloodpressure measurement. Data is recorded continuously for the duration ofthe study using Notocord software (Kalamazoo, Mich.) and stored aselectronic digital signals. Parameters measured are blood pressure(systolic, diastolic and mean arterial pressure) and heart rate.

Assay 4 In Vivo Evaluation of Antihypertensive Effects in the ConsciousDOCA-Salt Rat Model of Hypertension

CD rats (male, adult, 200-300 grams, Charles River Laboratory, USA) areallowed a minimum of 48 hours acclimation upon arrival at the testingsite before they are placed on a high salt diet. One week after thestart of the high salt diet (8% in food or 1% NaCl in drinking water), adeoxycorticosterone acetate (DOCA) pellet (100 mg, 90 days release time,Innovative Research of America, Sarasota, Fla.) is implantedsubcutaneously and unilateral nephrectomy is performed. At this time,the animals are also surgically implanted with small rodentradiotransmitters for blood pressure measurement (see Assay 3 fordetails). The animals are allowed to recover with appropriate postoperative care. Study design, data recording, and parameters measured issimilar to that described for Assay 3.

Assay 5 In Vivo Evaluation of Antihypertensive Effects in the ConsciousDahl/SS Rat Model of Hypertension

Male, Dahl salt sensitive rats (Dahl/SS, 6-7 weeks of age from CharlesRiver Laboratory, USA) are allowed at least 48 hours of acclimation uponarrival at the testing site before they were placed on a 8% NaCl highsalt diet (TD.92012, Harlan, USA) then surgically implanted with smallrodent radiotransmitters for blood pressure measurement (see Assay 3 fordetails). The animals are allowed to recover with appropriate postoperative care. At approximately 4 to 5 weeks from the start of highsalt diet, these animals are expected to become hypertensive. Once thehypertension level is confirmed, these animals are used for the studywhile continued with the high salt diet to maintain their hypertensionlevel. Study design, data recording, and parameters measured is similarto that described in Assay 3.

While the present invention has been described with reference tospecific aspects or embodiments thereof, it will be understood by thoseof ordinary skilled in the art that various changes can be made orequivalents can be substituted without departing from the true spiritand scope of the invention. Additionally, to the extent permitted byapplicable patent statutes and regulations, all publications, patentsand patent applications cited herein are hereby incorporated byreference in their entirety to the same extent as if each document hadbeen individually incorporated by reference herein.

1. (canceled)
 2. The process of claim 18, where X is selected frompyrazole, imidazole, triazole, benzotriazole, furan, pyrrole, tetrazole,pyrazine, thiophene, oxazole, isoxazole, thiazole, isothiazole,oxadiazole, thiadiazole, pyridazine, pyridine, pyrimidine, pyran,benzimidazole, benzoxazole, benzothiazole, pyridylimidazole, andpyridyltriazole.
 3. The process of claim 2, where X is selected frompyrazole, triazole, benzotriazole, tetrazole, oxazole, isoxazole,thiazole, pyridazine, pyrimidine, and pyridyltriazole.
 4. The process ofclaim 18, where R¹ is selected from —OR⁷ and —NR⁸R⁹, where R⁷ is H, R⁸is H or —OH, and R⁹ is H.
 5. The process of claim 18, where: R¹ is —OR⁷;and R⁷ is selected from —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R¹⁰, —C₁₋₆alkylene-NR¹²R¹³, —C₁₋₆alkylene-C(O)R³¹,—C₀₋₆alkylenemorpholinyl, —C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

or R¹ is —NR⁸R⁹; R⁸ is selected from —OC(O)R¹⁴, —CH₂COOH, —O-benzyl,pyridyl, and —OC(S)NR¹⁵R¹⁶; and R⁹ is H; or R¹ is —NR⁸R⁹; R⁸ is selectedfrom —OC(O)R¹⁴, —CH₂COOH, —O-benzyl, pyridyl, and —OC(S)NR¹⁵R¹⁶; and R⁹is —C₁₋₆alkyl or —C(O)R¹⁷; or R¹ is —NR⁸R⁹; R⁸ is selected from H of and—OH; and R⁹ is selected from —C₁₋₆alkyl and —C(O)R¹⁷; or R¹ is —OR⁷ andR² is taken together with R⁷ to form —CR¹⁸R¹⁹—; or R¹ is —NR⁸R⁹ and R²is taken together with R⁸ to form —C(O)—.
 6. The process of claim 18,where R¹ is —OR⁷, where R⁷ is selected from H, —C₁₋₈alkyl,—C₁₋₃alkylene-C₆₋₁₀aryl, —C₀₋₆alkylenemorpholinyl, and

where R³² is —C₁₋₆alkyl; and where each alkyl group is optionallysubstituted with 1 to 8 fluoro atoms.
 7. The process of claim 18, whereR² is H.
 8. The process of claim 18, where R³ is absent or is selectedfrom H; halo; —C₀₋₅alkylene-OH; —NH₂; —C₁₋₆alkyl; —CF₃; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁ alkylene-COOR²¹;—C(O)NR²²R²³; —NHC(O)R²⁴; ═O; —NO₂; —C(CH₃)═N(OH); phenyl optionallysubstituted with one or two groups independently selected from halo,—OH, —CF₃, —OCH₃, —NHC(O)CH₃, and phenyl; naphthalenyl; pyridinyl;pyrazinyl; pyrazolyl optionally substituted with methyl; thiophenyloptionally substituted with methyl or halo; furanyl; and—CH₂-morpholinyl; and R²¹ is H.
 9. The process of claim 18, where R³ is—C₀₋₁alkylene-COOR²¹; and R²¹ is selected from —C₁₋₆ alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl, —C₁₋₃ alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl,—[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R²⁵, —C₁₋₆alkylene-NR²⁷R²⁸, —C₁₋₆alkylene-C(O)R³³, —C₀₋₆ alkylenemorpholinyl, —C₁₋₆ alkylene-SO₂—C₁₋₆alkyl,


10. The process of claim 18, where R³ is absent or is selected from H;halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; —NHC(O)R²⁴; ═O; phenyl optionally substituted with one ortwo groups independently selected from halo, —OH, and —OCH₃; pyridinyl;and pyrazinyl; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is H or —C₁₋₆alkyl; R²³is selected from —C₁₋₆alkyl, —(CH₂)₂OH, —(CH₂)₂OCH₃, —(CH₂)₂SO₂NH₂, and—C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together to forma saturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo or —OH, and optionally containing an oxygen atomin the ring; and R²⁴ is phenyl substituted with —OCH₃.
 11. The processof claim 18, where R⁴ is absent or is selected from H; —OH; —C₁₋₆alkyl;—C₁₋₂alkylene-COOR³⁵; —CH₂OC(O)CH(R³⁶)NH₂; —CH₂CH(OH)CH₂OH; pyridinyl;and phenyl or benzyl optionally substituted with one or more groupsselected from halo, —COOR³⁵, —OCH₃, —OCF₃, and —SCF₃; and R³⁵ is H. 12.The process of claim 18, where R⁴ is selected from —OCH₂OC(O)CH₃;—CH₂OP(O)(OH)₂; —C₁₋₂alkylene-COOR³⁵; and phenyl or benzyl substitutedwith at least one —COOR³⁵ group; where R³⁵ is selected from —C₁₋₆alkyl,—C₁₋₃alkylene-C₆₋₁₀aryl, —C₁₋₃alkylene-C₁₋₉hetero aryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R²⁵, —C₁₋₆ alkylene-NR²⁷R²⁸,—C₁₋₆ alkylene-C(O)R³³, —C₀₋₆alkylenemorpholinyl,—C₁₋₆alkylene-SO₂—C₁₋₆alkyl,


13. The process of claim 18, where R⁴ is selected from H; —OH;—C₁₋₂alkylene-COOR³⁵; pyridinyl; and phenyl or benzyl optionallysubstituted with one or more groups selected from halo and —OCH₃; andR³⁵ is H.
 14. The process of claim 18, where a is 0; or a is 1 and R⁵ isselected from halo and —CN.
 15. The process of claim 18, where b is 0;or b is 1 and R⁶ is selected from Cl, F, —OH, —CH₃, —OCH₃, and —CF₃; orb is 2 and each R⁶ is independently halo, —OH, —CH₃, or —OCH₃; or b is 3and each R⁶ is independently halo or —CH₃.
 16. The process of claim 18,where R¹ is OR⁷; R² is H; X is selected from pyrazole, triazole,benzotriazole, tetrazole, oxazole, isoxazole, thiazole, pyridazine,pyrimidine, and pyridyltriazole; R³ is absent or is selected from H;halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; phenyl optionally substituted with one or two groupsindependently selected from halo, —OH, and —OCH₃; pyridinyl; andpyrazinyl; R⁴ is selected from H; —OH; —C₁₋₂alkylene-COOR³⁵; pyridinyl;and phenyl or benzyl optionally substituted with one or more groupsselected from halo and —OCH₃; a is 0; or a is 1 and R⁵ is selected fromhalo and —CN; b is 0; or b is 1 and R⁶ is selected from Cl, F, —OH,—CH₃, —OCH₃, and —CF₃; or b is 2 and each R⁶ is independently halo, —OH,—CH₃, or —OCH₃; or b is 3 and each R⁶ is independently halo or —CH₃; R⁷is selected from H, —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₀₋₆alkylenemorpholinyl, and

R³² is —C₁₋₆alkyl; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is H or —C₁₋₆alkyl;R²³ is selected from —C₁₋₆alkyl, —(CH₂)₂OH, —(CH₂)₂OCH₃, —(CH₂)₂SO₂NH₂,and —C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together toform a saturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo or —OH, and optionally containing an oxygen atomin the ring; R²⁴ is phenyl substituted with —OCH₃; and R³⁵ is H; andwhere each alkyl group in R¹ is optionally substituted with 1 to 8fluoro atoms.
 17. The process of claim 18, where R¹ is OR⁷; R² is H; Xis selected from pyrazole, triazole, benzotriazole, tetrazole, oxazole,isoxazole, thiazole, pyridazine, and pyrimidine; R³ is absent or isselected from H; halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; phenyl substituted with one or two groups independentlyselected from halo, —OH, and —OCH₃; pyridinyl; and pyrazinyl; R⁴ isselected from H, —OH, and phenyl optionally substituted with a halogroup; a is 0; or a is 1 and R⁵ is halo; b is 0; or b is 1 and R⁶ ishalo or —CH₃; or b is 2 and each R⁶ is independently halo, —OH, —CH₃, or—OCH₃; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is —C₁₋₆alkyl; R²³ is —C₁₋₆alkylor —C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together toform a saturated —C₃₋₅heterocycle optionally substituted with halo or—OH; and R²⁴ is phenyl substituted with —OCH₃.
 18. A process forpreparing a compound of formula I:

or a pharmaceutically acceptable salt thereof, comprising the step ofcoupling a compound of formula 1 with a compound of formula 2:

to produce the compound of formula I; where R¹ is selected from —OR⁷ and—NR⁸R⁹; R² is H or —P(O)(OH)₂ or R² is taken together with R⁷ to form—CR¹⁸R¹⁹— or is taken together with R⁸ to form —C(O)—; X is a—C₁₋₉heteroaryl; R³ is absent or is selected from H; halo;—C₀₋₅alkylene-OH; —NH₂; —C₁₋₆alkyl; —CF₃; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; —NO₂; —C(CH₃)═N(OH); phenyl optionally substituted withone or two groups independently selected from halo, —OH, —CF₃—OCH₃,—HC(O)CH₃, and phenyl; naphthalenyl; pyridinyl; pyrazinyl; pyrazoleoptionally substituted with methyl; thiophenyl optionally substitutedwith methyl or halo; furanyl; and —CH₂-morpholinyl; and R³, whenpresent, is attached to a carbon atom; R⁴ is absent or is selected fromH; —OH; —C₁₋₆alkyl; —C₁₋₂alkylene-COOR³⁵; —CH₂OC(O)CH(R³⁶)NH₂;—OCH₂OC(O)CH(R³⁶)NH₂; —OCH₂OC(O)CH₂; —CH₂OP(O)(OH)₂; —CH₂CH(OH)CH₂OH;—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl; pyridinyl; and phenyl or benzyloptionally substituted with one or more groups selected from halo,—COOR³⁵, —OCH₃—OCF₃, and —SCF₃; and R⁴, when present, is attached to acarbon or nitrogen atom; or R³ and R⁴ are taken together to form-phenylene-O—(CH₂)₁₋₃— or -phenylene-O—CH₂—CHOH—CH₂—; a is 0 or 1; R⁵ isselected from halo, —CH₃—CF₃, and —CN; b is 0 or an integer from 1 to 3;each R⁶ is independently selected from halo, —OH, —CH₃, —OCH₃, and —CF₃;R⁷ is selected from H, —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R¹⁰, —C₁₋₆alkylene-NR¹²R¹³, —C₁₋₆alkylene-C(O)R³¹,—C₀₋₆alkylenemorpholinyl, —C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

R¹⁰ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR¹²R¹³, —CH[CH(CH₃)₂]—NH₂,—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, and —CH(NH₂)CH₂COOCH₃; and R¹² and R¹³are independently selected from H, —C₁₋₆alkyl, and benzyl; or R¹² andR¹³ are taken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or —(CH₂)₂O(CH₂)₂—;and R³¹ is selected from —O—C₁₋₆alkyl, —O-benzyl, and —NR¹²R¹³; R³² is—C₁₋₆alkyl or —C₀₋₆alkylene-C₆₋₁₀aryl; R⁸ is selected from H, —OH,—OC(O)R¹⁴, —CH₂COOH, —O-benzyl, pyridyl, and —OC(S)NR¹⁵R¹⁶; R¹⁴ isselected from H, —C₁₋₆alkyl, —C₆₋₁₀aryl, —OCH₂—C₆₋₁₀aryl,—CH₂O—C₆₋₁₀aryl, and —NR¹⁵R¹⁶; and R¹⁵ and R¹⁶ are independentlyselected from H and —C₁₋₄alkyl; R⁹ is selected from H, —C₁₋₆alkyl, and—C(O)R¹⁷; and R¹⁷ is selected from H, —C₁₋₆alkyl, —C₃₋₇cycloalkyl,—C₆₋₁₀aryl, and —C₁₋₉heteroaryl; R¹⁸ and R¹⁹ are independently selectedfrom H, —C₁₋₆alkyl, and —O—C₃₋₇cycloalkyl, or R¹⁸ and R¹⁹ are takentogether to form ═O; R²⁰ is selected from H and —C₁₋₆alkyl; R²¹ and R³⁵are independently selected from H, —C₁₋₆alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R²⁵, —C₁₋₆alkylene-NR²⁷R²⁸, —C₁₋₆alkylene-C(O)R³³,—C₀₋₆alkylenemorpholinyl, —C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

R²⁵ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR²⁷R²⁸, —CH[CH(CH₃)₂]—NH₂,—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, and —CH(NH₂)CH₂COOCH₃; R²⁷ and R²⁸ areindependently selected from H, —C₁₋₆alkyl, and benzyl; or R²⁷ and R²⁸are taken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or —(CH₂)₂O(CH₂)₂—; R³³is selected from —O—C₁₋₆alkyl, —O-benzyl, and —NR²⁷R²⁸; and R³⁴ is—C₁₋₆alkyl or —C₀₋₆alkylene-C₆₋₁₀aryl; R²² and R²³ are independentlyselected from H, —C₁₋₆alkyl, —CH₂COOH, —(CH₂)₂OH, —(CH₂)₂OCH₃,—(CH₂)₂SO₂NH₂, —(CH₂)₂N(CH₃)₂, —C₀₋₁alkylene-C₃₋₇cycloalkyl, and—(CH₂)₂-imidazolyl; or R²² and R²³ are taken together to form asaturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo, —OH, —COOH, or —CONH₂; and optionally containingan oxygen atom in the ring; R²⁴ is selected from —C₁₋₆alkyl;—C₀₋₁alkylene-O—C₁₋₆alkyl; phenyl optionally substituted with halo or—OCH₃; and —C₁₋₉heteroaryl; and R³⁶ is selected from H, —CH(CH₃)₂,phenyl, and benzyl; where each alkyl group in R¹, R³, and R⁴ isoptionally substituted with 1 to 8 fluoro atoms; and where the methylenelinker on the biphenyl is optionally substituted with one or two—C₁₋₆alkyl groups or cyclopropyl; P¹ is H or an amino-protecting groupselected from t-butoxycarbonyl, trityl, benzyloxycarbonyl,9-fluorenylmethoxycarbonyl, formyl, trimethylsilyl, andt-butyldimethylsilyl; and where the process further comprisesdeprotecting the compound of formula 1 when P¹ is an amino protectinggroup.
 19. (canceled)
 20. A process for preparing a compound of formulaI:

or a pharmaceutically acceptable salt thereof, comprising the step ofdeprotecting a compound selected from:

or a salt thereof to produce the compound of formula I; where R¹ isselected from —OR⁷ and —NR⁸R⁹; R^(1P) is selected from —O—P³, —NHP², and—NH(O—P⁴); R² is H or —P(O)(OH)₂ or R² is taken together with R⁷ to form—CR¹⁸R¹⁹— or is taken together with R⁸ to form —C(O)—; X is a—C₁₋₉heteroaryl; R³ is absent or is selected from H; halo;—C₀₋₅alkylene-OH; —NH₂; C₁₋₆alkyl; —CF₃; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; —NO₂; —C(CH₃)═N(OH); phenyl optionally substituted withon or two groups independently selected from halo, —OH, —CF₃—OCH₃,—HC(O)CH₃, and phenyl; naphthalenyl; pyridinyl; pyrazinyl; pyrazoleoptionally substituted with methyl; thiophenyl optionally substitutedwith methyl or halo; furanyl; and —CH₂-morpholinyl; and R³, whenpresent, is attached to a carbon atom; R^(3P) is selected from—C₀₋₅alkylene-O—P⁴, —C₀₋₁alkylene-COO—P³, and phenyl substituted with—O—P⁴; R⁴ is absent or is selected from H; —OH; —C₁₋₆alkyl;—C₁₋₂alkylene-COOR³⁵; —CH₂OC(O)CH(R³⁶)NH₂; —OCH₂OC(O)CH(R³⁶)NH₂;—OCH₂OC(O)CH₃; —CH₂OP(O)(OH)₂; —CH₂CH(OH)CH₂OH;—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl; pyridinyl; and phenyl or benzyloptionally substituted with one or more groups selected from halo,—COOR³⁵, —OCH₃—OCF₃ and —SCF₃; and R⁴, when present, is attached to acarbon or nitrogen atom; R^(4P) is selected from —O—P⁴;—C₁₋₂alkylene-COO—P³; and phenyl or benzyl substituted with —COO—P³; orR³ and R⁴ are taken together to form -phenylene-O—(CH₂)₁₋₃— or-phenylene-O—CH₂—CHOH—CH₂; a is 0 or 1; R⁵ is selected from halo,—CH₃—CF₃, and —CN; b is 0 or an integer from 1 to 3; each R⁶ isindependently selected from halo, —OH, —CH₃, —OCH₃, and —CF₃; R⁷ isselected from H, —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R¹⁰, —C₁₋₆alkylene-NR¹²R¹³, —C₁₋₆alkylene-C(O)R³¹,—C₀₋₆alkylenemorpholinyl, —C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

R¹⁰ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR¹²R¹³, —CH[CH(CH₃)₂]—NH₂,—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, and —CH(NH₂)CH₂COOCH₃; and R¹² and R¹³are independently selected from H, —C₁₋₆alkyl, and benzyl; or R¹² andR¹³ are taken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or —(CH₂)₂O(CH₂)₂—;and R³¹ is selected from —O—C₁₋₆alkyl, —O-benzyl, and —NR¹²R¹³; R³² is—C₁₋₆alkyl or —C₀₋₆alkylene-C₆₋₁₀aryl; R⁸ is selected from H, —OH,—OC(O)R¹⁴, —CH₂COOH, —O-benzyl, pyridyl, and —OC(S)NR¹⁵R¹⁶; R¹⁴ isselected from H, —C₁₋₆alkyl, —C₆₋₁₀aryl, —OCH₂—C₆₋₁₀aryl,—CH₂O—C₆₋₁₀aryl, and —NR¹⁵R¹⁶; and R¹⁵ and R¹⁶ are independentlyselected from H and —C₁₋₄alkyl; R⁹ is selected from H, —C₁₋₆alkyl, and—C(O)R¹⁷; and R¹⁷ is selected from H, —C₁₋₆alkyl, —C₃₋₇cycloalkyl,—C₆₋₁₀aryl, and —C₁₋₉heteroaryl; R¹⁸ and R¹⁹ are independently selectedfrom H, —C₁₋₆alkyl, and —O—C₃₋₇cycloalkyl, or R¹⁸ and R¹⁹ are takentogether to form ═O; R²⁰ is selected from H and —C₁₋₆alkyl; R²¹ and R³⁵are independently selected from H, —C₁₋₆alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R²⁵, —C₁₋₆alkylene-NR²⁷R²⁸, C₁₋₆alkylene-C(O)R³³,—C₀₋₆alkylenemorpholinyl, —C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

R²⁵ is selected from —C₁₋₆alkyl, —O—C₁₋₆alkyl, —C₃₋₇cycloalkyl,—O—C₃₋₇cycloalkyl, phenyl, —O-phenyl, —NR²⁷R²⁸, —CH[CH(CH₃)₂]—NH₂,—CH[CH(CH₃)₂]—NHC(O)O—C₁₋₆alkyl, and —CH(NH₂)CH₂COOCH₃; R²⁷ and R²⁸ areindependently selected from H, —C₁₋₆alkyl, and benzyl; or R²⁷ and R²⁸are taken together as —(CH₂)₃₋₆—, —C(O)—(CH₂)₃—, or —(CH₂)₂O(CH₂)₂—; R³³is selected from —O—C₁₋₆alkyl, —O-benzyl, and —NR²⁷R²⁸; and R³⁴ is—C₁₋₆alkyl or —C₀₋₆alkylene-C₆₋₁₀aryl; R²² and R²³ are independentlyselected from H, —C₁₋₆alkyl, —CH₂COOH, —(CH₂)₂OH, —(CH₂)₂OCH₃,—(CH₂)₂SO₂NH₂, —(CH₂)₂N(CH₃)₂, —C₀₋₁alkylene-C₃₋₇ cycloalkyl, and—(CH₂)₂-imidazolyl; or R²² and R²³ are taken together to form asaturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo, —OH, —COOH, or —CONH₂; and optionally containingan oxygen atom in the ring; R²⁴ is selected from —C₁₋₆alkyl;—C₀₋₁alkylene-O—C₁₋₆alkyl; phenyl optionally substituted with halo or—OCH₃; and —C₁₋₉heteroaryl; and R³⁶ is selected from H, —CH(CH₃)₂,phenyl, and benzyl; where each alkyl group in R¹, R³, and R⁴ isoptionally substituted with 1 to 8 fluoro atoms; and where the methylenelinker on the biphenyl is optionally substituted with one or two—C₁₋₆alkyl groups or cyclopropyl; P² is an amino-protecting groupselected from t-butoxycarbonyl, trityl, benzyloxycarbonyl,9-fluorenylmethoxycarbonyl, formyl, trimethylsilyl, andt-butyldimethylsilyl; P³ is a carboxy-protecting group selected frommethyl, ethyl, t-butyl, benzyl, p-methoxybenzyl, 9-fluorenylmethyl,trimethylsilyl, t-butyldimethylsilyl, and diphenylmethyl; and P⁴ is ahydroxyl-protecting group selected from —C₁₋₆alkyl, triC₁₋₆alkylsilyl,—C₁₋₆alkanoyl, benzoyl, benzyl, p-methoxybenzyl, 9-fluorenylmethyl, anddiphenylmethyl. 21-25. (canceled)
 26. The process of claim 20, where Xis selected from pyrazole, imidazole, triazole, benzotriazole, furan,pyrrole, tetrazole, pyrazine, thiophene, oxazole, isoxazole, thiazole,isothiazole, oxadiazole, thiadiazole, pyridazine, pyridine, pyrimidine,pyran, benzimidazole, benzoxazole, benzothiazole, pyridylimidazole, andpyridyltriazole.
 27. The process of claim 26, where X is selected frompyrazole, triazole, benzotriazole, tetrazole, oxazole, isoxazole,thiazole, pyridazine, pyrimidine, and pyridyltriazole.
 28. The processof claim 20, where R¹ is selected from —OR⁷ and —NR⁸R⁹, where R⁷ is H,R⁸ is H or —OH, and R⁹ is H.
 29. The process of claim 20, where: R¹ is—OR₇; and R⁷ is selected from —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃,—C₁₋₆alkylene-OC(O)R¹⁰, —C₁₋₆alkylene-NR¹²R¹³, —C₁₋₆alkylene-C(O)R³¹,—C₀₋₆alkylenemorpholinyl, —C₁₋₆alkylene-SO₂—C₁₋₆alkyl,

or R¹ is —NR⁸R⁹; R⁸ is selected from —OC(O)R¹⁴, —CH₂COOH, —O-benzyl,pyridyl, and —OC(S)NR¹⁵R¹⁶; and R⁹ is H; or R¹ is —NR⁸R⁹; R⁸ is selectedfrom —OC(O)R¹⁴, —CH₂COOH, —O-benzyl, pyridyl, and —OC(S)NR¹⁵R¹⁶; and R⁹is —C₁₋₆alkyl or —C(O)R¹⁷; or R¹ is —NR⁸R⁹; R⁸ is selected from H and—OH; and R⁹ is selected from —C₁₋₆alkyl and —C(O)R¹⁷; or R¹ is —OR⁷ andR² is taken together with R⁷ to form —CR¹⁸R¹⁹—; or R¹ is —NR⁸R⁹ and R²is taken together with R⁸ to form —C(O)—.
 30. The process of claim 20,where R¹ is —OR⁷, where R⁷ is selected from H, —C₁₋₈alkyl,—C₁₋₃alkylene-C₆₋₁₀aryl, —C₀₋₆alkylenemorpholinyl, and

where R³² is —C₁₋₆alkyl; and where each alkyl group is optionallysubstituted with 1 to 8 fluoro atoms.
 31. The process of claim 20, whereR² is H.
 32. The process of claim 20, where R³ is absent or is selectedfrom H; halo; —C₀₋₅alkylene-OH ; —NH₂; —C₁ ₋₆alkyl; —CF₃;—C₃₋₇cycloalkyl; —C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰;—C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³; —NHC(O)R²⁴; ═O; —NO₂; —C(CH₃)═N(OH);phenyl optionally substituted with one or two groups independentlyselected from halo, —OH, —CF₃, —OCH₃, —NHC(O)CH₃, and phenyl;naphthalenyl; pyridinyl; pyrazinyl; pyrazolyl optionally substitutedwith methyl; thiophenyl optionally substituted with methyl or halo;furanyl; and —CH₂-morpholinyl; and R²¹ is H.
 33. The process of claim20, where R³ is —C₀₋₁alkylene-COOR²¹; and R²¹ is selected from—C₁₋₆alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl, —C₁₋₃alkylene-C₁₋₉heteroaryl,—C₃₋₇cycloalkyl, —[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R²⁵,—C₁₋₆alkylene-NR²⁷R²⁸, —C₁₋₆alkylene-C(O)R³³, —C₀₋₆alkylenemorpholinyl,—C₁₋₆alkylene-SO₂—C₁₋₆alkyl,


34. The process of claim 20, where R³ is absent or is selected from H;halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; phenyl optionally substituted with one or two groupsindependently selected from halo, —OH, and —OCH₃; pyridinyl; andpyrazinyl; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is H or —C₁₋₆alkyl; R²³ isselected from —C₁₋₆alkyl, —(CH₂)₂OH, —(CH₂)₂OCH₃, —(CH₂)₂SO₂NH₂, and—C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together to forma saturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo or —OH, and optionally containing an oxygen atomin the ring; and R²⁴ is phenyl substituted with —OCH₃.
 35. The processof claim 20, where R⁴ is absent or is selected from H; —OH; —C₁₋₆alkyl;—C₁₋₂alkylene-COOR³⁵; —CH₂OC(O)CH(R³⁶)NH₂; —CH₂CH(OH)CH₂OH; pyridinyl;and phenyl or benzyl optionally substituted with one or more groupsselected from halo, —COOR³⁵, —OCH₃, —OCF₃, and —SCF₃; and R³⁵ is H. 36.The process of claim 20, where R⁴ is selected from —OCH₂OC(O)CH₃;—CH₂OP(O)(OH)₂; —C₁₋₂alkylene-COOR³⁵; and phenyl or benzyl substitutedwith at least one —COOR³⁵ group; where R³⁵ is selected from —C₁₋₆alkyl,—C₁₋₃alkylene-C₆₋₁₀aryl, —C₁₋₃alkylene-C₁₋₉heteroaryl, —C₃₋₇cycloalkyl,—[(CH₂)₂O]₁₋₃CH₃, —C₁₋₆alkylene-OC(O)R²⁵, —C₁₋₆alkylene-NR²⁷R²⁸,—C₁₋₆alkylene-C(O)R³³, —C₀₋₆alkylenemorpholinyl,—C₁₋₆alkylene-SO₂—C₁₋₆alkyl,


37. The process of claim 20, where R⁴ is selected from H; —OH;—C₁₋₂alkylene-COOR³⁵; pyridinyl; and phenyl or benzyl optionallysubstituted with one or more groups selected from halo and —OCH₃; andR³⁵ is H.
 38. The process of claim 20, where a is 0; or a is 1 and R⁵ isselected from halo and —CN.
 39. The process of claim 20, where b is 0;or b is 1 and R⁶ is selected from Cl, F, —OH, —CH₃, —OCH₃, and —CF₃; orb is 2 and each R⁶ is independently halo, —OH, —CH₃, or —OCH₃; or b is 3and each R⁶ is independently halo or —CH₃.
 40. The process of claim 20,where R¹ is OR⁷; R² is H; X is selected from pyrazole, triazole,benzotriazole, tetrazole, oxazole, isoxazole, thiazole, pyridazine,pyrimidine, and pyridyltriazole; R³ is absent or is selected from H;halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;—NHC(O)R²⁴; ═O; phenyl optionally substituted with one or two groupsindependently selected from halo, —OH, and —OCH₃; pyridinyl; andpyrazinyl; R⁴ is selected from H; —OH; —C₁₋₂alkylene-COOR³⁵; pyridinyl;and phenyl or benzyl optionally substituted with one or more groupsselected from halo and —OCH₃; a is 0; or a is 1 and R⁵ is selected fromhalo and —CN; b is 0; or b is 1 and R⁶ is selected from Cl, F, —OH,—CH₃, —OCH₃, and —CF₃; or b is 2 and each R⁶ is independently halo, —OH,—CH₃, or —OCH₃; or b is 3 and each R⁶ is independently halo or —CH₃; R⁷is selected from H, —C₁₋₈alkyl, —C₁₋₃alkylene-C₆₋₁₀aryl,—C₀₋₆alkylenemorpholinyl, and

R³² is —C₁₋₆alkyl; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is H or —C₁₋₆alkyl;R²³ is selected from —C₁₋₆alkyl, —(CH₂)₂OH, —(CH₂)₂OCH₃, —(CH₂)₂SO₂NH₂,and —C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together toform a saturated or partially unsaturated —C₃₋₅heterocycle optionallysubstituted with halo or —OH, and optionally containing an oxygen atomin the ring; R²⁴ is phenyl substituted with —OCH₃; and R³⁵ is H; andwhere each alkyl group in R¹ is optionally substituted with 1 to 8fluoro atoms.
 41. The process of claim 20, where R¹ is OR⁷; R² is H; Xis selected from pyrazole, triazole, benzotriazole, tetrazole, oxazole,isoxazole, thiazole, pyridazine, and pyrimidine; R³ is absent or isselected from H; halo; —C₀₋₅alkylene-OH; —C₁₋₆alkyl; —C₃₋₇cycloalkyl;—C₀₋₂alkylene-O—C₁₋₆alkyl; —C(O)R²⁰; —C₀₋₁alkylene-COOR²¹; —C(O)NR²²R²³;NHC(O)R²⁴; ═O; phenyl substituted with one or two groups independentlyselected from halo, —OH, and —OCH₃; pyridinyl; and pyrazinyl; R⁴ isselected from H, —OH, and phenyl optionally substituted with a halogroup; a is 0; or a is 1 and R⁵ is halo; b is 0; or b is 1 and R⁶ ishalo or —CH₃; or b is 2 and each R⁶ is independently halo, —OH, —CH₃, or—OCH₃; R²⁰ is —C₁₋₆alkyl; R²¹ is H; R²² is —C₁₋₆alkyl; R²³ is —C₁₋₆alkylor —C₀₋₁alkylene-C₃₋₇cycloalkyl; or R²² and R²³ are taken together toform a saturated —C₃₋₅heterocycle optionally substituted with halo or—OH; and R²⁴ is phenyl substituted with —OCH₃.